https://hill.pictures/Recent content on Hill's SpaceHugoenhillexed@email.com (hillexed)hillexed@email.com (hillexed)Sat, 10 May 2025 17:47:25 +0000https://hill.pictures/meniscus12/polishing_figuring/114484788934808798/Sat, 10 May 2025 17:47:25 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114484788934808798/Five or so 30 minute long sessions of long parabolizing W strokes have finally turned my center hill into a center hole. The dip at around 80% to 90% diameter remains, while the 90% to 100% diameter edge zone is turned up. I made two changes to get better pitch contact: I am filling a plastic container with hot water and pressing the pitch to the glass underwater, and I am only polishing for 30 minutes at a time instead of going for a full hour.https://hill.pictures/meniscus12/polishing_figuring/114472425426904282-mirrorcell/Thu, 08 May 2025 13:23:13 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114472425426904282-mirrorcell/I have made a contraption called a “mirror cell” it traps naughty glass so I can examine its sinshttps://hill.pictures/leavitt/observing/galaxies-with-camera/Thu, 24 Apr 2025 13:52:15 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/galaxies-with-camera/Today, I tried finding some galaxies. I couldn’t see M101, couldn’t see M105, but did see M81 and M82 by eye. It was tough, but I finally took a phone pic. I decided to give Pingu Camera a try… and the phone plus printed adapter plus phone remote shutter plus waiting a while for vibrations to die down worked! I got a picture of both M81 and M82!!https://hill.pictures/meniscus12/polishing_figuring/114370457436532728/Sun, 20 Apr 2025 13:11:25 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114370457436532728/I’m around 10 hours into polishing, and it looks like I’m very close to polished out! I can see barely any tiny pits under a microscope. I think I’m done. Next up, figuring. I can test a mirror’s shape easily. I have been doing that already despite not quite being done with polishing. The problem with a thin mirror is that glass (and anything else) will happily bend a few hundred nanometers under its own weight.https://hill.pictures/leavitt/observing/baffling/Tue, 15 Apr 2025 18:55:12 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/baffling/My 8" telescope has been upgraded with some new printed shields to block unwanted light near the top. Pics of said light blocking baffles. Also added a mount for my pifinder.https://hill.pictures/meniscus12/polishing_figuring/114320620644061026/Fri, 11 Apr 2025 17:57:15 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114320620644061026/Polishing continues. I’ve noticed that my short center over center strokes seem to be creating a hill in the center of this mirror, so I’ve switched to longer 1/2-diameter strokes and 1/3 side to side motion in order to wear down the center of the mirror. It seems to be working, according to these ronchi test images before and after. I’m jumping the gun a little by figuring while polishing but there’s a long way to go so I should be fine.https://hill.pictures/leavitt/observing/2025-lunar-eclipse/Fri, 14 Mar 2025 08:13:51 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/2025-lunar-eclipse/Lunar eclipse! Funny enough the telescope made things brighter and therefore even during totality it looked less contrasting through the telescope than by eyehttps://hill.pictures/meniscus12/polishing_figuring/114132733870068977/Sun, 09 Mar 2025 13:35:11 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114132733870068977/My mirror is now reflective enough to see the entire surface and get my first Ronchi test image! But I’m not done with polishing - it may look reflective by eye, but the same region under a microscope reveals tiny pits left over from 5 micron grit are still there. I’m not polished out until all those are gone.https://hill.pictures/meniscus12/polishing_figuring/114118218877365378/Fri, 07 Mar 2025 00:03:50 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114118218877365378/My pitch lap polishing tool wasn’t making good contact with the center of my mirror. I can tell because I’m just beginning polishing and so I can see that the mirror’s outside is more reflective than the inside. Also, the tool looks unevenly worn. I tried heating up the tool using a tub of hot water so the pitch would flow and then pressing the tool against the mirror some more (pictured) but it seems to have only helped slightly.https://hill.pictures/meniscus12/polishing_figuring/114010225679670502/Sat, 15 Feb 2025 22:19:44 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/114010225679670502/Another hour and a half of polishing and my piece of glass is looking much more reflective! I was stroking with tool on top, but I noticed the center of the pitch lap wasn’t making good contact. I suspect the plaster backing tool that the mirror rests on isn’t evenly supporting the mirror; it picked up a slightly wavy surface I was hoping wouldn’t cause issues. When I poured the tool I used wax paper to ensure it wouldn’t stick to the mirror, and the wax paper crumpled slightly from being flat on a non-flat mirror surface.https://hill.pictures/meniscus12/polishing_figuring/113969890168393693/Sat, 08 Feb 2025 19:21:53 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/113969890168393693/I finally started polishing this 12" mirror! It has taken so long and many failures to get here. I took the pitch lap tool that I made and carved some bonus channels into it, squirted on cerium oxide mixed with water, and got polishing. An hour and a half later, the outside of my mirror is polished and now is smooth enough to reflect light! It looks like my pitch lap wasn’t pressed for long rnough to make good contact with the mirror, though, because I can see that only a ring around the outside is being worn down, not the center.https://hill.pictures/meniscus12/polishing_figuring/113937108915491908-pitchlap/Mon, 03 Feb 2025 00:25:11 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/polishing_figuring/113937108915491908-pitchlap/I created a pitch lap, a tool used for the last two steps of mirror making. I will use it for polishing and figuring. Pitch, also known as asphalt, is a viscous liquid like honey and will flow to match the shape of the mirror when pressed against it.https://hill.pictures/leavitt/observing/2025-mars-sketch/Fri, 24 Jan 2025 03:42:12 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/2025-mars-sketch/Rough mars sketch! The atmosphere is not cooperating but there’s this big Africa-shaped gray region!https://hill.pictures/leavitt/observing/mars-behind-moon/Tue, 14 Jan 2025 04:15:36 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/mars-behind-moon/Goodbye mars! (Zoom in!) Taken using my 3D printed telescope, with a crowd of friends invited to watch the occultation of mars by the moon! The phone I was taking photos on ran out of battery, so I hastily threw a friend’s iphone into the holder just in time to capture these.https://hill.pictures/blog/2025-mars-occultation/Mon, 13 Jan 2025 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/2025-mars-occultation/(Zoom into these photos to see Mars!) Taken using my Hadley 3D printed telescope, with a crowd of friends invited to watch the occultation of mars by the moon! The phone I was taking photos on ran out of battery, so I hastily threw a friend’s iphone into the holder just in time to capture these.https://hill.pictures/leavitt/observing/leavitt_firstlight/Wed, 01 Jan 2025 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/leavitt_firstlight/I finally used my new 8" telescope with a working mirror cell! Report: Jupiter is nice and bright! M42 is so much brighter than in my first telescope! It’s green and I can the bat wings and texture in the trapezium along with four stars! There are so many stars everywhere! High power reveals flaws. High power stars look like ovals. After some investigation, my secondary mirror wasn’t centered in the eyepiece view.https://hill.pictures/leavitt/buildingblog/113692888699399482-complete/Sat, 21 Dec 2024 21:16:46 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/113692888699399482-complete/8" telescope: COMPLETE!! It has literally taken all year, but my second telescope ever is done! It’s made of 3D printed parts, metal tubes, nuts and bolts, and a mirror I hand-polished over the course of 8 months! I’m very proud.https://hill.pictures/leavitt/mount/mirrorcell/Fri, 20 Dec 2024 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/mount/mirrorcell/The part of the telescope that holds a mirror in place is called the “mirror cell”. The simplest way to hold a mirror in place is with three dabs of silicone glue. If glue is too hard, it can pull on the mirror and the stress will distort its shape on a scale of hundreds of nanometers, which is bad. Small mirrors can usually get away with just three dabs of glue.https://hill.pictures/meniscus12/grinding/113646109855266237/Fri, 13 Dec 2024 15:00:18 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113646109855266237/I ran out of leftover 12 micron, so I’m going to 5 micron. The longer scratch seems to be entirely gone, and the short scratch is now two tiny slices less than a millimeter long. Hopefully it’ll grind out. Current cumulative grinding time: 46 hours.https://hill.pictures/meniscus12/grinding/113642383177604142/Thu, 12 Dec 2024 23:12:33 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113642383177604142/Went back to 12 micron grinding. 1 hour and 45 minutes later, the scratches are now little dots spaced along a line. There aren’t any more lines trailing in from the edge, at least, so I hope that counts as a success for my beveling.https://hill.pictures/meniscus12/grinding/113603534124619229/Fri, 06 Dec 2024 02:32:43 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113603534124619229/Tragedy! I thought beveling the edge would help, but… I see scratches. Again. And only after 20 minutes of grinding. (I drew pencil marks next to them for visibility). Long, too. Maybe my sanding made particles of 400 grit fly into my tool? Aaaaarghhttps://hill.pictures/meniscus12/grinding/113603226703066483/Fri, 06 Dec 2024 01:14:33 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113603226703066483/I bought some 400 grit alox sandpaper and glued it to a failed 3D print to act as a bootleg grinding stone. Hopefully this will stop the bevel from introducing particles.https://hill.pictures/meniscus12/grinding/113572264473740830/Sat, 30 Nov 2024 14:00:26 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113572264473740830/Another hour of 5 micron grinding and, unlike the first time, no scratches! But then I looked closer. By using my phone flashlight, I saw one very thin and not very deep scratch (a “sleek”). That’s fine. I also saw some thicker scratches around 1-2mm long intersecting the edge - see the photo. Maybe those marks are from bits of glass that were torn from the beveled edge? This adds credence to my theory that my previous scratch problems were bevel problems, not a speck of coarse grit contaminating.https://hill.pictures/meniscus12/grinding/113545359875966388/Mon, 25 Nov 2024 19:58:15 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113545359875966388/Mirror grinding with the newly refurbished tool is going extremely well! After two hours I ran out of 30 micron aluminum oxide grit and moved on to 12 micron. (You can move on when you’ve eliminated pits from the previous bigger grit size, but since previously I was at 5 micron, I didn’t have any pits and could move on whenever I wanted, but I also wanted to grind the tool as smooth as possible).https://hill.pictures/meniscus12/grinding/113535509383830474/Sun, 24 Nov 2024 02:13:08 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113535509383830474/My refurbished tool is ready to go. However, I have to go back a few sizes to coarser grit to ensure the tool is ground down evenly to make good contact across its full area. From 5 micron (the last size of grit needed) back to 30 micron size grit I go… Thankfully, after an hour of grinding, it looks like it’s wearing evenly. It’s sliding smoothly across the mirror.https://hill.pictures/meniscus12/grinding/113533283531809577/Sat, 23 Nov 2024 16:47:04 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113533283531809577/15 minutes of more grinding created even more scratches, starting from the edge and moving in. I think maybe I wasn’t using enough liquid and my tool was knocking off bits of the edge glass and dragging them inwards. To avoid any possibility of my tool having coarse grit caught in the channels in between tiles, I remade my tool. I bought some “tabletop epoxy” which takes 3 days to cure and covered my existing tool with it, then put on a new layer of tiles.https://hill.pictures/meniscus12/grinding/113500761083446869/Sun, 17 Nov 2024 22:56:11 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113500761083446869/Another tragedy! As I move to 12 and then 5 micron aluminum oxide grits, the final stages of fine grinding, scratches are showing up. I keep losing tiles from my tile tool, too. A scratch means some particle bigger than the current abrasive size is being introduced - maybe grit from earlier stages of grinding was trapped in between narrow gaps gaps in my tool’s tiles? I probably have to go back to a coarser grit to get it out.https://hill.pictures/leavitt/buildingblog/113479310709983250-mirrorwaiting/Thu, 14 Nov 2024 04:01:05 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/113479310709983250-mirrorwaiting/Update: at long last, my now aluminized mirror is finally being shipped back to me! A timeline of recent events: October 19: The mirror is aluminized. The aluminizer notes that he will wait a week to ensure the coating cures properly (reasonable and expected) November 1: I am told that the mirror is “all set to send it out” November 7: I ask for any shipping updates November 10: I get a reply saying “I’ll do it tomorrow”https://hill.pictures/hadley/observing/2024mars/Sat, 09 Nov 2024 04:54:16 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/observing/2024mars/I looked at mars with my 4.5" telescope. Previously it just looked like a big circle, but adding a 2x barlow lens to get to 150x zoom made it big enough I could make out a tiny line of slightly darker area on Mars! That’s the first time that I saw any detail on mars! That’s neat, but also wow my standards are so low.https://hill.pictures/meniscus12/grinding/113437426375544501-crackfixing/Wed, 06 Nov 2024 18:29:20 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113437426375544501-crackfixing/I’m slowly dealing with the crack’s aftermath. Slowly, I ground through the big hole I made when burnishing the crack. As I ground it down over the week, the crack wasn’t visible under the loupe unless I put a flashlight sideways and used a finger to cover the top of the mirror, illuminating from the side. After watching the hole get smaller and smaller, I took a look… and the crack was still barely visible.https://hill.pictures/meniscus12/grinding/113377434240142332/Sun, 27 Oct 2024 04:12:33 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113377434240142332/Tragedy! I dropped my tool onto the glass from an inch up. I thought I was fine, but close inspection revealed a crack a millimeter long. I was advised to try to burnish it out because the crack could travel very deep and spread. I ended up putting a screw in a drill and using the head as a bootleg buffing wheel with my 30 micron water mix to try to dig out the crack and its subsurface damage.https://hill.pictures/blog/2024-not-real-numbers/Fri, 25 Oct 2024 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/2024-not-real-numbers/I rediscovered the xkcd up goer five text editor, which lets you type using only the 1000 most common english words. So here’s my attempt at writing a description of something: Not Real Numbers We know how to do many number problems. Number problems with adding are easy. Adding the same number over and over is also easy. If you take a number and add it many times, the same number of times as that number, you get a box number.https://hill.pictures/leavitt/buildingblog/113351965296706923/Tue, 22 Oct 2024 16:15:28 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/113351965296706923/My 8" mirror that I polished by hand is officially a mirror! The person with a vacuum chamber, who I gave my mirror to two months ago, finally aluminized my mirror and sent me a picture! It’s shiny and reflective like a mirror should be! Now it just has to survive being shipped back…https://hill.pictures/hadley/observing/comet-tsuchinshan-atlas/Thu, 17 Oct 2024 12:49:09 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/observing/comet-tsuchinshan-atlas/Cell phone pic of Comet Tsuchinshan-Atlas! It was visible faintly in the sky by eye too! Weridly it seemed brighter by eye than through the telescope. That could be because my telescope wasn’t shielded from a nearby streetlight and stray light created a brighter background?https://hill.pictures/meniscus12/grinding/113279745934153017/Wed, 09 Oct 2024 22:09:08 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113279745934153017/18 minutes later, I ran out of grit and the unground region is less than 0.5mm wide. I’m calling it: good enough! I’m done grinding the back! Total back grinding time: 5 hours 57 minuteshttps://hill.pictures/meniscus12/grinding/113279508518291294/Wed, 09 Oct 2024 21:08:45 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113279508518291294/Grinding the back has gone smoothly. At first I didn’t get good contact between tool and mirror; one orientation would slide freely but after turning the mirror 90 degrees any attempts to slide would lock up. Eventually the tool wore down and I got good contact. In these pictures, my goal is to spread the frosted area (where the mirror has been sanded down to a sphere) everywhere. Any smooth areas are where the grit hasn’t made good contact (lower areas).https://hill.pictures/meniscus12/grinding/113279259474660098/Wed, 09 Oct 2024 20:05:25 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113279259474660098/When grinding thin mirrors, there is something called the “twyman effect”: grinding one side adds stress that can slightly curl the mirror’s other side. It can lead to slight astigmatism in thin mirrors that disappears once you grind the back side to relieve that stress. (See https://quinsightspectre.com/16-25-f-3-1-meniscus-mirror/ !) To avoid any problems, I decided to follow the wisdom and grind my meniscus mirror’s convex back through #220 grit. Plus, it would get rid of any saddle shape, which I could see existed when beginning to grind the front.https://hill.pictures/leavitt/buildingblog/113209648668007237-aluminizing-summary/Fri, 27 Sep 2024 13:02:28 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/113209648668007237-aluminizing-summary/My 8" mirror is done; now I need to aluminize it. The final step of making a telescope mirror, after spending months grinding glass into a parabola, is to cover the perfectly shaped glass in a thin layer of shiny reflective metal. The most common technique is melting aluminum in a vacuum chamber so the atoms gently float onto the glass and stick. (There’s also a newer spray silvering technique that involves $400 of chemicals but amortizes out to cheap for many mirrors.https://hill.pictures/meniscus12/grinding/113184023572757096/Mon, 23 Sep 2024 00:25:40 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113184023572757096/Looks like after 3 hours of grinding at #220 grit, the divot that has been in my glass since the start has been ground out! Yay! I’m glad I went back to coarser grit; this could have easily been six hours had I stuck with #320. A mirror with a short focal length will make objects look brighter because they’re zoomed out, but is much harder to parabolize at the very end of the mirror making process.https://hill.pictures/meniscus12/grinding/113172632403185939/Sat, 21 Sep 2024 00:08:45 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113172632403185939/I’ve gone to 200 grit from the finer 320 grit. I’m glad I did; an hour of grinding later and my last tiny divot still has’t ground away. Had I stuck with 320 grit, I’d need to spend twice as long to get to where I am now. Hopefully another hour will get it out.https://hill.pictures/hadley/observing/partial-lunar-eclipse-2024/Wed, 18 Sep 2024 04:40:01 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/observing/partial-lunar-eclipse-2024/Partialest of partial lunar eclipseshttps://hill.pictures/meniscus12/grinding/113141711532899269/Sun, 15 Sep 2024 13:05:10 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113141711532899269/A problem! After 6 hours of total grinding, I measured my mirror’s focal length and found it was 37". That’s weird because before it was 39" - maybe my hands were applying pressure in the center of the tool? Lower focal length means more zoomed out (and brighter) telescope views, but makes the final stage of parabolizing harder. If focal length / mirror diameter is less than 4, you also get “coma” that distorts the stars towards the edges of the view.https://hill.pictures/meniscus12/grinding/113131388427910923/Fri, 13 Sep 2024 17:19:52 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/113131388427910923/Today’s hour of mirror grinding has completely gotten rid of the low zone! Now I just need to grind down through that one tiny divot. I noticed it seemed like my tool was pushing the water I sprayed out off the mirror. I used a blade to try to carve notches in between my hexagonal tiles, and afterwards I could feel the tool sliding more smoothly, allowing water to flow between the tool and the mirror.https://hill.pictures/leavitt/observing/introducing-pingucam/Thu, 12 Sep 2024 04:32:14 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/observing/introducing-pingucam/Introducing… Pingu Camera. I bought a used DSLR for astrophotography four months ago hoping it would take better photos than my phone. I 3D printed an adapter for it to fit into a standard eyepiece slot. Unfortunately it was a bit of a failure for two reasons: firstly, this camera isn’t mirrorless, so it had a shutter inside it, and when that shutter flips up to take photos it sends vibrations through the entire telescope.https://hill.pictures/meniscus12/grinding/7368062-meniscus-mirror-afte/Tue, 20 Aug 2024 16:50:24 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/7368062-meniscus-mirror-afte/The cloudy part is where the grit has sanded the glass. Clearly part of the glass is higher and making less contact. I bet it’s because the furnace cement mold was slightly curved because the wooden mold was slightly curved thanks to the grain of the woodhttps://hill.pictures/meniscus12/grinding/7355552-12-meniscus-mirror/Mon, 19 Aug 2024 16:35:25 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/7355552-12-meniscus-mirror/My grinding tool is making cool patterns! You’re looking at water trapped under my 12" meniscus mirroe, and flowing between the channels in the home depot porcelain tiles on my grinding tool. Those tiles will grind flat eventually.https://hill.pictures/meniscus12/grinding/7347438-meniscus-mirror-gri/Sun, 18 Aug 2024 23:18:04 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/7347438-meniscus-mirror-gri/I got a table for $5 at a yard sale. It looks perfect for a mirror grinding setup after putting some weights on the bottom rack. Now that I’ve completed my 8" mirror polishing, it’s time to try my bigger telescope mirror project. Just making this blank took a lot of effort - now, to grind it. Let the grinding start!https://hill.pictures/hadley/buildingblog/7279657-the-planets-there/Tue, 13 Aug 2024 14:46:32 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/7279657-the-planets-there/Taken using my 4.5" telescope and phone! Both Mars and Jupiter fit into telescope view! Very annoying observing session. Tried to take photos of the ring nebula but missed; planet conjunction was extremely slightly out of focus and I didn’t see until morning, and I looked for but still couldn’t see M33. Couldn’t see any detail on mars by eye either; that should change as we get closer to opposition.https://hill.pictures/blog/sylvie-lords-fanart/Thu, 08 Aug 2024 04:53:23 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/sylvie-lords-fanart/@sylvie hi get fanarted for a fun game with neat movement mechanics There’s something inherently funny about someone who only knows how to descend ladders by backflippinghttps://hill.pictures/leavitt/buildingblog/7164387-8-mirror-actually/Sun, 04 Aug 2024 19:15:51 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/7164387-8-mirror-actually/Someone brought an extremely accurate “double pass autocollimator” tester to an amateur telescope maker meetup… and it showed an uniform shade of gray across the whole mirror, meaning no defects (ignore the circular reflections from the test stand). That means my mirror is an extremely smooth parabola! I’m done mirror grinding! 🎉 First mirror: complete! 🎉 That’s so cool! I thought I was slightly overparabolized based on my Foucalt testing.https://hill.pictures/mirror_polishing/7164387-8-mirror-actually/Sun, 04 Aug 2024 19:15:51 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/7164387-8-mirror-actually/Unable to find image 7164387-8-mirror-actually-image.png Unable to find image 7164387-8-mirror-actually-image2.png Someone brought an extremely accurate “double pass autocollimator” tester to an amateur telescope maker meetup… and it showed an uniform shade of gray across the whole mirror, meaning no defects (ignore the circular reflections from the test stand). That means my mirror is an extremely smooth parabola! I’m done mirror grinding! 🎉 First mirror: complete! 🎉 That’s so cool! I thought I was slightly overparabolized based on my Foucalt testing.https://hill.pictures/leavitt/mount/7122997-8-telescope-making/Thu, 01 Aug 2024 16:47:32 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/mount/7122997-8-telescope-making/8" mount v1 complete! After several days of designing, 3D printing, and experiencing the joys of my favorite telescope related activity, hacksawing through metal, I managed to assemble a complete mount! Design-wise, I had to replace 0.5" screws with 0.75" screws in a few places because the redesigned EMT tubes were too close together. The telescope uses only 0.5" screws, so it would have been nice to match, but it’s fine for an one-off.https://hill.pictures/leavitt/mount/7122883-8-telescope-making/Thu, 01 Aug 2024 14:37:48 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/mount/7122883-8-telescope-making/Every telescope needs a mount, to hold it up and let it rotate. 6 months ago, I thought that I was close to the finish line, since all I had to do was make a mirror and a mount! Then the mirror took six months. Now I need to sit down and actually finish this mount. My 4.5" scope uses a truss of EMT steel tubes and the scope sits on a wide C-shaped part.https://hill.pictures/leavitt/buildingblog/7059454-8-telescope-mirror/Sat, 27 Jul 2024 23:40:39 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/7059454-8-telescope-mirror/I did a tiny bit more parabolizing, then re-measured my mirror. Last time, my spreadsheet and measurements told me my outer zone needed to focus tiny bit farther and my lower zone needed to be a tiny bit closer. To dig the inner zone out, I did some W strokes with lots of mirror movement on the tool edge, and then used long center over center strokes with a tiny offset to dig everywhere but a tiny strip of outside.https://hill.pictures/mirror_polishing/7059454-8-telescope-mirror/Sat, 27 Jul 2024 23:40:39 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/7059454-8-telescope-mirror/Unable to find image image2_1.jpeg Unable to find image image2_1.jpeg I did a tiny bit more parabolizing, then re-measured my mirror. Last time, my spreadsheet and measurements told me my outer zone needed to focus tiny bit farther and my lower zone needed to be a tiny bit closer. To dig the inner zone out, I did some W strokes with lots of mirror movement on the tool edge, and then used long center over center strokes with a tiny offset to dig everywhere but a tiny strip of outside.https://hill.pictures/leavitt/buildingblog/6966242-8-telescope-mirror/Sat, 20 Jul 2024 23:47:54 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/6966242-8-telescope-mirror/I’ve switched to using the Foucalt test and a Couder mask for parabolizing. The Foucalt test is more precise (but more annoying) than the Ronchi test, but my local astronomy club has a foucalt testing rig with a micrometer that lets me measure very precise details of where different regions of the mirror focus light, so it’s more accurately moveable than my handheld Ronchi tester. I built a cardboard “Couder mask” to block off regions of my mirror to see where the edge and center are focusing light to separately.https://hill.pictures/mirror_polishing/6966242-8-telescope-mirror/Sat, 20 Jul 2024 23:47:54 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/6966242-8-telescope-mirror/Unable to find image 6966242-8-telescope-mirror-image.png I’ve switched to using the Foucalt test and a Couder mask for parabolizing. The Foucalt test is more precise (but more annoying) than the Ronchi test, but my local astronomy club has a foucalt testing rig with a micrometer that lets me measure very precise details of where different regions of the mirror focus light, so it’s more accurately moveable than my handheld Ronchi tester.https://hill.pictures/meniscus12/grinding/6719304-meniscus-mirror-gri/Wed, 17 Jul 2024 02:07:25 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/6719304-meniscus-mirror-gri/(Attempt 1) This time I bought some new porcelain tiles from a local store for $5. Apparently glaze on tiles are slightly softer than porcelain, but per advice I just placed the tiles upside down. Mirror sat below, then plastic wrap on top, then tiles, and finally dental stone gets mixed and poured on top. Dental stone is a waterproof plaster that hardens fast; last time it hardened in my bucket after just 15 mins of mixing.https://hill.pictures/meniscus12/grinding/6731913-meniscus-mirror-mak/Thu, 04 Jul 2024 13:16:20 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/grinding/6731913-meniscus-mirror-mak/To grind my 12" blank into a mirror, I need a grinding tool. Since the glass is already curved, I’m going to make a grinding tool for my slumped telescope blank using these ceramic tiles I bought and dental stone, a waterproof plaster! The tiles are hard and will resist the grinding from grit pieces; they’re placed onto the curved glass so the tool takes its curved shape, and dental stone will be poured over this and harden into a convex tool for grinding with hard ceramic pieces sticking out.https://hill.pictures/meniscus12/draping/6533692-meniscus-mirror-dra/Thu, 27 Jun 2024 20:41:38 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/6533692-meniscus-mirror-dra/I got the news from my local glass studio in an all-caps email that said nothing but “IT WORKED!” Look at this! My glass is now clearly curved, around 1/4" taller at the sides than at the center! That’s very close to f/4, my goal! SLUMPING DRAPING: SUCCESS Weirdly, even though the mirror is the right shape, the cement form seems to have warped. The top face is now flat, and the bottom is now curved - which is weird because originally the bottom was flat and the top was curved.https://hill.pictures/leavitt/buildingblog/6533527-8-mirror-grinding/Thu, 20 Jun 2024 13:46:20 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/6533527-8-mirror-grinding/I’m at the final step of polishing a telescope mirror: turning a sphere shaped piece of glass into a parabola shaped piece of glass, called “figuring” or “parabolizing”. I messed up, twice, and since then I have been regrinding my glass back to a sphere for figuring attempt #3. Today, after several months, I finally have a spherical enough surface to start figuring attempt #3! Here’s both a Ronchi test and a Foucalt test.https://hill.pictures/mirror_polishing/6533527-8-mirror-grinding/Thu, 20 Jun 2024 13:46:20 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/6533527-8-mirror-grinding/Unable to find image verystraight_20240610_150033.jpg Unable to find image 6533527-8-mirror-grinding-image.png I’m at the final step of polishing a telescope mirror: turning a sphere shaped piece of glass into a parabola shaped piece of glass, called “figuring” or “parabolizing”. I messed up, twice, and since then I have been regrinding my glass back to a sphere for figuring attempt #3. Today, after several months, I finally have a spherical enough surface to start figuring attempt #3!https://hill.pictures/meniscus12/draping/5979550-meniscus-mirror-the/Wed, 15 May 2024 14:31:55 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5979550-meniscus-mirror-the/My goal of making meniscus mirrors is in sight! Now that I have a properly shaped cement form and a circle of glass cut out of a used countertop, I just need a computer controlled kiln to heat them up in. There happened to be an artist showcase near me, so I went and talked to a glass artist. She suggested I could find a kiln by… asking a studio if I could rent space in their kiln.https://hill.pictures/blog/5927714-hey-an-aurora/Sat, 11 May 2024 16:25:09 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/5927714-hey-an-aurora/I saw the aurora! It looked like light pollution at first, and I only realized what it was when I noticed the underwhelming “clouds” were in a different place after ten seconds. An hour later they had slight tints of red and green and distinct ray-like shapes! Very cool. Phone camera picked up way more color and detail than I could see by eye, and long 8s exposures picked up even more.https://hill.pictures/meniscus12/draping/5827198-meniscus-mirror-atte/Sat, 04 May 2024 14:45:50 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5827198-meniscus-mirror-atte/Bought some new furnace cement. Reused the same mold as before. Gave it four coats of spray polyurethane, sanded with #320 sandpaper before the last coat, taped up paper to the edge, mixed and poured cement and hurt my hand when my 3D printed spatula cracked in half. Lots of water ended up leaking out of the sides, which I was worried would be a bad thing and dry it out, so I added more water on top after the first day.https://hill.pictures/meniscus12/draping/5759720-meniscus-mirror-atte/Sun, 28 Apr 2024 23:27:02 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5759720-meniscus-mirror-atte/I carved a new wood mold and used the last of my furnace cement on attempt #4… and because I was working with 1/3 a bucket of cement, I ended up with something very thin that cracked when I tried to lift it off the wood mold. Sigh I only waited one day before trying to remove it, and I patted it dry with a paper towel. I think both of these were mistakes - the longer it sits wet, the harder it gets as crystals grow.https://hill.pictures/leavitt/buildingblog/5602988-8-mirror-grinding/Wed, 17 Apr 2024 16:50:10 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/5602988-8-mirror-grinding/It’s been a while but I gave the 8" mirror some grinding. I’m on my way back to sphere, undoing parabolizing attempt #2. 30 minutes of grinding seems to have created some turned down edge and a hole in the middle. Great. I put the mirror into the telescope, leaned it against a big crate again, and I was able to use it to see the moon! It’s amazing that even though I’m not done figuring, it’s smooth enough I can see things in space.https://hill.pictures/mirror_polishing/5602988-8-mirror-grinding/Wed, 17 Apr 2024 16:50:10 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/5602988-8-mirror-grinding/Unable to find image IMG_20240417_000708615_1.jpg Unable to find image 20240416_233201_124816.jpg It’s been a while but I gave the 8" mirror some grinding. I’m on my way back to sphere, undoing parabolizing attempt #2. 30 minutes of grinding seems to have created some turned down edge and a hole in the middle. Great. I put the mirror into the telescope, leaned it against a big crate again, and I was able to use it to see the moon!https://hill.pictures/blog/559502-free-mirror/Wed, 17 Apr 2024 00:15:17 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/559502-free-mirror/So I was talking to new local friends and telling them about telescopes and someone says “I have a mirror sitting on my table, is that something that could be useful?” and so after picking it up I now have a ginormous 12.25" mirror that’s 2.25" thick!! …now what do I do with it? Honestly I’m tempted to make a scope out of it… but that would take money and I’d need to learn new skills like woodworking.https://hill.pictures/meniscus12/draping/5307567-the-rock-displeased/Thu, 28 Mar 2024 16:03:45 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5307567-the-rock-displeased/I finally saw my friend’s kiln! It’s a big kiln. I took the cement mold (the wrongly shaped one) and cast it into the flames for displeasing me. Looks like the kiln can successfully get up to 1200 degrees F! The problem is, the kiln controller can only go up to one target temperature. For the actual glass slumping, I will need a ramp/soak controller, which can let me program it to hold at a certain temperature for some amount of time then move onto another temperature.https://hill.pictures/meniscus12/draping/5275309-meniscus-mirror-atte/Tue, 26 Mar 2024 03:10:41 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5275309-meniscus-mirror-atte/…the cement form’s curvature isn’t right. I measured the sagitta (how deep the curve is in the middle compared to the edge) and it’s 1/16". it should be around 1/4". This would make a telescope that’s 12 feet long. AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAARGH I CNCed mold’s shape wrong. I have two choices: I can either grind/sand down the edges of my cement form into a deeper curve (probably releasing tons of bad to breathe in dust), or start the process all over again with new wood.https://hill.pictures/meniscus12/draping/5272725-meniscus-mirror-atte/Tue, 26 Mar 2024 03:08:49 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5272725-meniscus-mirror-atte/I GOT IT OUT!!! FINALLYYYYYY AFTER THREE TRIES AND SO MUCH POURING I HAVE A KILN RESISTANT THING THAT CAN FIT MY FURNACE CEMENT!!!https://hill.pictures/meniscus12/draping/5219356-12-meniscus-mirror/Fri, 22 Mar 2024 15:02:42 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/5219356-12-meniscus-mirror/In addition to grinding an 8" mirror, I’m trying a technique to make big thin 12" mirrors. See the #meniscusmirror tag for more. Previously, setting things on fire didn’t improve the problem. Now I have a $35 tub of castable furnace cement (amazon had it for $14 cheaper than home depot). It’s dry sand that needs water and throws up clouds of dust, glad I have a respirator from covid.https://hill.pictures/leavitt/buildingblog/5125808-8-parabolizing-atte/Sun, 17 Mar 2024 18:05:44 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/5125808-8-parabolizing-atte/My local astronomy club has a foucalt tester, and today I tested that mirror after 30 seconds of parabolizing. It revealed a big turned down edge (yahoo…) and some slight zones in the center of the mirror. I knew those zones existed - heck, you can even see the slight non-sphericalness in the second image of my “close enough to spherical!” celebration - but the radius of curvature changes rapidly where one zone meets another instead of smoothly blending.https://hill.pictures/mirror_polishing/5125808-8-parabolizing-atte/Sun, 17 Mar 2024 18:05:44 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/5125808-8-parabolizing-atte/Unable to find image 512image2.png Unable to find image 512image.png My local astronomy club has a foucalt tester, and today I tested that mirror after 30 seconds of parabolizing. It revealed a big turned down edge (yahoo…) and some slight zones in the center of the mirror. I knew those zones existed - heck, you can even see the slight non-sphericalness in the second image of my “close enough to spherical!https://hill.pictures/leavitt/buildingblog/5108307-8-mirror-parabolizi/Sat, 16 Mar 2024 14:38:47 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/5108307-8-mirror-parabolizi/I’m parabolizing my telescope mirror - I’ve ground it to a sphere shape, and now I’m grinding a tiny bit more to change its shape precisely into a parabola. I’ve done 3 grinding sessions for a total of 34 minutes of grinding. Here’s a Ronchi picture of my current progress. Mel’s online Ronchi calculator has overlaid some semi-transparent white lines which show the ideal Ronchi grid of a somewhat parabolized mirror.https://hill.pictures/mirror_polishing/5108307-8-mirror-parabolizi/Sat, 16 Mar 2024 14:38:47 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/5108307-8-mirror-parabolizi/Unable to find image image.png Unable to find image texereau-normal I’m parabolizing my telescope mirror - I’ve ground it to a sphere shape, and now I’m grinding a tiny bit more to change its shape precisely into a parabola. I’ve done 3 grinding sessions for a total of 34 minutes of grinding. Here’s a Ronchi picture of my current progress. Mel’s online Ronchi calculator has overlaid some semi-transparent white lines which show the ideal Ronchi grid of a somewhat parabolized mirror.https://hill.pictures/leavitt/buildingblog/5104400-8-mirror-grinding/Sat, 16 Mar 2024 00:43:46 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/5104400-8-mirror-grinding/I’m in the home stretch - my goal is to turn this sphere shaped mirror into a parabola shaped mirror. The final stage of mirror grinding is called either parabolizing, because you’re making a parabola, or figuring, because you have to measure carefully and that involves numbers which are also called figures. You use a stroke that goes up and down fast and side to side slowly in a big zigzag, called a W stroke, to remove a tiny bit of glass from both the center and the edge, as seen in the first picture (from Mel Bartels’ site).https://hill.pictures/mirror_polishing/5104400-8-mirror-grinding/Sat, 16 Mar 2024 00:43:46 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/5104400-8-mirror-grinding/Unable to find image parabolastrats.png Unable to find image 510400-1.png Unable to find image 510400-2.png I’m in the home stretch - my goal is to turn this sphere shaped mirror into a parabola shaped mirror. The final stage of mirror grinding is called either parabolizing, because you’re making a parabola, or figuring, because you have to measure carefully and that involves numbers which are also called figures. You use a stroke that goes up and down fast and side to side slowly in a big zigzag, called a W stroke, to remove a tiny bit of glass from both the center and the edge, as seen in the first picture (from Mel Bartels’ site).https://hill.pictures/leavitt/buildingblog/4995398-8-mirror-grinding/Sun, 10 Mar 2024 18:11:13 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4995398-8-mirror-grinding/This site is my secret weapon: https://www.bbastrodesigns.com/ronchi.html It’s a slightly janky javascript app made by some old telescope maker in Oregon, and it lets you get quantitative measurements from all those Ronchi pictures. Very important. Looks like my outer zone focuses light at around 0.066 in from my desired radius of curvature, and inner zone focuses light at around 0.1 in. (There’s probably big error bars on both those numbers).https://hill.pictures/mirror_polishing/4995398-8-mirror-grinding/Sun, 10 Mar 2024 18:11:13 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4995398-8-mirror-grinding/Unable to find image 4995398-pic-1.png Unable to find image 4995398-pic-2.png Unable to find image texereauabberation.png This site is my secret weapon: https://www.bbastrodesigns.com/ronchi.html It’s a slightly janky javascript app made by some old telescope maker in Oregon, and it lets you get quantitative measurements from all those Ronchi pictures. Very important. Looks like my outer zone focuses light at around 0.066 in from my desired radius of curvature, and inner zone focuses light at around 0.https://hill.pictures/leavitt/buildingblog/4987442-8-mirror-grinding-u/Sat, 09 Mar 2024 21:30:19 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4987442-8-mirror-grinding-u/I’M SO CLOSE TO A SPHERE (You know you’re a sphere when the lines are completely straight. See this infographic for more) total mirror grinding time: TWENTY GODDAMN HOURShttps://hill.pictures/mirror_polishing/4987442-8-mirror-grinding-u/Sat, 09 Mar 2024 21:30:19 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4987442-8-mirror-grinding-u/Unable to find image IMG_20240309_162343854~2.jpg Unable to find image IMG_20240309_162149283~2.jpg Unable to find image IMG_20240309_161749437~2.jpg I’M SO CLOSE TO A SPHERE (You know you’re a sphere when the lines are completely straight. See this infographic for more) total mirror grinding time: TWENTY GODDAMN HOURShttps://hill.pictures/leavitt/buildingblog/4970990-mirror-grinding-upda/Fri, 08 Mar 2024 23:53:47 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4970990-mirror-grinding-upda/I did 20 minutes without my center paper cutout and managed to dig a tiny zone in the center. Yaaaaay. Then I spent two hours ignoring it and trying to get the outside zone down. On the plus side that outer zone at 70%+ diameter looks spherical now. Now I have a choice: I think I’m close to a parabola. With that deeper center, if I can flatten the inner edge of that transition I’m very close.https://hill.pictures/mirror_polishing/4970990-mirror-grinding-upda/Fri, 08 Mar 2024 23:53:47 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4970990-mirror-grinding-upda/Unable to find image image-6~2.png Unable to find image image-5~2.png I did 20 minutes without my center paper cutout and managed to dig a tiny zone in the center. Yaaaaay. Then I spent two hours ignoring it and trying to get the outside zone down. On the plus side that outer zone at 70%+ diameter looks spherical now. Now I have a choice: I think I’m close to a parabola.https://hill.pictures/leavitt/buildingblog/4929167-8-mirror-grinding/Wed, 06 Mar 2024 21:33:57 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4929167-8-mirror-grinding/I’m using an advanced technique: cutting out pieces of paper and putting them under the tool while pressing to avoid certain areas of the tool touching the mirror. I know I have a hole in the middle, so by blocking the middle from wearing down I can concentrate my wearing on the outer zones without making the center even deeper. Looks like after a few hours I’ve managed to get the outer zone almost completely spherical!https://hill.pictures/mirror_polishing/4929167-8-mirror-grinding/Wed, 06 Mar 2024 21:33:57 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4929167-8-mirror-grinding/Unable to find image IMG_20240306_124746726_1.jpg Unable to find image IMG_20240306_160753289~2.jpg Unable to find image IMG_20240306_160449695~2.jpg I’m using an advanced technique: cutting out pieces of paper and putting them under the tool while pressing to avoid certain areas of the tool touching the mirror. I know I have a hole in the middle, so by blocking the middle from wearing down I can concentrate my wearing on the outer zones without making the center even deeper.https://hill.pictures/leavitt/buildingblog/4890338-a-ronchi-test-infogr/Mon, 04 Mar 2024 23:05:04 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4890338-a-ronchi-test-infogr/Check out this infographic of how to read the Ronchi tests of my telescope mirror! I’ve been posting lots of pictures like this as I grind, and this tells you how to interpret what the pictures say about a mirror’s shape. The Ronchi test can be used to roughly measure a mirror’s shape and see any turned down edge (“TDE”), and with a computer program to analyze them, even give some quantitative measurements.https://hill.pictures/mirror_polishing/4890338-a-ronchi-test-infogr/Mon, 04 Mar 2024 23:05:04 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4890338-a-ronchi-test-infogr/Unable to find image ronchi_infographic.png Unable to find image 4890338-a-ronchi-test-infogr-image.png Check out this infographic of how to read the Ronchi tests of my telescope mirror! I’ve been posting lots of pictures like this as I grind, and this tells you how to interpret what the pictures say about a mirror’s shape. The Ronchi test can be used to roughly measure a mirror’s shape and see any turned down edge (“TDE”), and with a computer program to analyze them, even give some quantitative measurements.https://hill.pictures/leavitt/buildingblog/4887618-8-mirror-grinding/Mon, 04 Mar 2024 21:00:51 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4887618-8-mirror-grinding/Two hours of mirror grinding brought me from the first pic to the second! The center zone got so big! It’s so much straighter! I’m much closer to a spherical mirror!https://hill.pictures/mirror_polishing/4887618-8-mirror-grinding/Mon, 04 Mar 2024 21:00:51 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4887618-8-mirror-grinding/Unable to find image IMG_20240301_215655700~2.jpg Unable to find image IMG_20240304_154953737~2.jpg Two hours of mirror grinding brought me from the first pic to the second! The center zone got so big! It’s so much straighter! I’m much closer to a spherical mirror!https://hill.pictures/leavitt/buildingblog/4842476-current-mirror-progr/Sat, 02 Mar 2024 16:36:41 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4842476-current-mirror-progr/The center zone, visible in the first pic as the inner area with red on the left and black on the right, is a bit more smooth and has grown from around 50% diameter to around 80% diameter. The outer zone is still a gradual slope but it focuses light to around a centimeter or so further than the inner zone. Previously that outer zone was extremely too tall, so my goal was to reduce it, and compared to a few weeks ago it looks reduced but not gone.https://hill.pictures/mirror_polishing/4842476-current-mirror-progr/Sat, 02 Mar 2024 16:36:41 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4842476-current-mirror-progr/Unable to find image IMG_20240301_215405266~2.jpg Unable to find image IMG_20240301_215655700~2.jpg The center zone, visible in the first pic as the inner area with red on the left and black on the right, is a bit more smooth and has grown from around 50% diameter to around 80% diameter. The outer zone is still a gradual slope but it focuses light to around a centimeter or so further than the inner zone.https://hill.pictures/meniscus12/draping/4611581-setting-things-on-fi/Mon, 26 Feb 2024 17:10:05 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/4611581-setting-things-on-fi/After a few weeks of drying, the wood was very warped and I couldn’t get the furnace cement out; perhaps it had bonded to the wood. What’s the difference between wood and furnace cement? Cement is heat resistant, and wood is very flammable. So I started a fire. I grabbed some sticks and some newspaper as kindling and piled it on, then lit it on fire inside a barbecue. Turns out I suck at starting a fire - I didn’t have enough small sticks to sustain a fire for a while and catch the large wooden mold on fire.https://hill.pictures/meniscus12/draping/4543544-meniscus-mirror-mold/Wed, 21 Feb 2024 16:43:26 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/4543544-meniscus-mirror-mold/To make a meniscus mirror I need a precisely-shaped thing that will stay the same shape even at 600C. On Jan 31, I machined out a new piece of wood, sprayed it with polyurethane, and then poured in furnace cement! …but several days of drying later, I couldn’t get the cement out of the mold. It stuck to the wood too well. In attempt #1 I used 3 coats of polyurethane, but in this I only used one.https://hill.pictures/leavitt/buildingblog/4519594-current-mirror-progr/Mon, 19 Feb 2024 17:46:10 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4519594-current-mirror-progr/Here’s my mirror in a Ronchi test and a Foucault test. I’ve managed to reduce the turned down edge to a very small area but it’s still there, visible in the ronchi as hooks at the edges and in the Foucault as a slight black zone at the bottom left of the image. I’ve also managed to dig a huge hole in the center of the mirror trying to fix that edge…https://hill.pictures/mirror_polishing/4519594-current-mirror-progr/Mon, 19 Feb 2024 17:46:10 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4519594-current-mirror-progr/Unable to find image IMG_20240217_151229501.jpg Unable to find image IMG_20240217_151451964.jpg Here’s my mirror in a Ronchi test and a Foucault test. I’ve managed to reduce the turned down edge to a very small area but it’s still there, visible in the ronchi as hooks at the edges and in the Foucault as a slight black zone at the bottom left of the image. I’ve also managed to dig a huge hole in the center of the mirror trying to fix that edge…https://hill.pictures/hadley/buildingblog/4497379-it-s-m42/Sat, 17 Feb 2024 00:15:58 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/4497379-it-s-m42/Since Orion was so high in the sky compared to my last photo I was curious if photos would look better… and they do! This is one 1/2s phone pic, scaled to hell and back to bring out the “bat wings”: big dark edges that go from bottom left to top right. Now I know there’s many ways to make this better, such as motorizing or a bigger telescope or stacking multiple pictures - but for just one phone pic this isn’t that bad!https://hill.pictures/leavitt/buildingblog/4488742-grinding-continues/Fri, 16 Feb 2024 02:39:57 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4488742-grinding-continues/It looks like there were pockets of air under the pitch. Leaving it alone for a week meant the bubbles seem to have popped and some areas sank downwards. This turned down edge is slowly going down but it still feels like an endless quest with no end in sight. Total grinding time so far: 8 hourshttps://hill.pictures/mirror_polishing/4488742-grinding-continues/Fri, 16 Feb 2024 02:39:57 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4488742-grinding-continues/Unable to find image IMG_20240213_161218564.jpg Unable to find image IMG_20240215_191112369~2.jpg Unable to find image IMG_20240213_152657507_HDR_1.jpg It looks like there were pockets of air under the pitch. Leaving it alone for a week meant the bubbles seem to have popped and some areas sank downwards. This turned down edge is slowly going down but it still feels like an endless quest with no end in sight. Total grinding time so far: 8 hourshttps://hill.pictures/leavitt/buildingblog/4414898-the-art-of-figuring/Thu, 08 Feb 2024 18:00:57 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4414898-the-art-of-figuring/This pretty art piece is actually a precise measurement of my progress in telescope mirror grinding. It looked fun enough out of context I decided to post it! You’re looking at multiple overlaid square images. Each one is a Ronchi test, which tells me the shape of my mirror on a nanometer scale in the shape of the red stripes. As I polish the mirror, it changes shape, so after 20 minutes of polishing I want to measure the new shape.https://hill.pictures/mirror_polishing/4414898-the-art-of-figuring/Thu, 08 Feb 2024 18:00:57 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4414898-the-art-of-figuring/Unable to find image ronchiart.png This pretty art piece is actually a precise measurement of my progress in telescope mirror grinding. It looked fun enough out of context I decided to post it! You’re looking at multiple overlaid square images. Each one is a Ronchi test, which tells me the shape of my mirror on a nanometer scale in the shape of the red stripes. As I polish the mirror, it changes shape, so after 20 minutes of polishing I want to measure the new shape.https://hill.pictures/leavitt/buildingblog/4322624-8-mirror-polishing/Fri, 02 Feb 2024 18:12:05 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4322624-8-mirror-polishing/To test the shape of a mirror, amateur telescope makers have a few tests which involve bouncing light off the mirror to see its shape. One cheap one is the Ronchi test, which sends light through a grating of fine lines, bounces off the mirror, and then you place the grating at the radius of convergence of your mirror so it blocks part of the light and reveals the mirror shape.https://hill.pictures/mirror_polishing/4322624-8-mirror-polishing/Fri, 02 Feb 2024 18:12:05 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4322624-8-mirror-polishing/Unable to find image IMG_20240126_215335157_1.jpg Unable to find image IMG_20240127_110757751.jpg Unable to find image IMG_20240130_005945275_1.jpg Unable to find image IMG_20240130_004837861.jpg To test the shape of a mirror, amateur telescope makers have a few tests which involve bouncing light off the mirror to see its shape. One cheap one is the Ronchi test, which sends light through a grating of fine lines, bounces off the mirror, and then you place the grating at the radius of convergence of your mirror so it blocks part of the light and reveals the mirror shape.https://hill.pictures/meniscus12/draping/4338060-meniscus-mirror-mold/Wed, 31 Jan 2024 22:34:45 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/4338060-meniscus-mirror-mold/To give a circle of glass (approximately) the right curve for a telescope mirro,, I want to make a precisely shaped mold that can withstand kiln temperatures. This technique makes what’s called a meniscus mirror. Last time I tried this, the wood delaminated and came apart at the boundary where one plank was glued to another. This time, I’m spraying the wood with polyurethane spray on both the front AND back side, to avoid any warping before I put the furnace cement in.https://hill.pictures/mirror_polishing/4338060-meniscus-mirror-mold/Wed, 31 Jan 2024 22:34:45 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4338060-meniscus-mirror-mold/Unable to find image IMG_20240131_170731472_1.jpg Unable to find image IMG_20240131_172405688_1.jpg To give a circle of glass (approximately) the right curve for a telescope mirro,, I want to make a precisely shaped mold that can withstand kiln temperatures. This technique makes what’s called a meniscus mirror. Last time I tried this, the wood delaminated and came apart at the boundary where one plank was glued to another. This time, I’m spraying the wood with polyurethane spray on both the front AND back side, to avoid any warping before I put the furnace cement in.https://hill.pictures/leavitt/buildingblog/4310523-8-mirror-polishing/Tue, 30 Jan 2024 17:11:15 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4310523-8-mirror-polishing/After all that setup, actually polishing a mirror is surprisingly simple. First you put your mirror on your tool and apply pressure so the pitch flows and takes the shape of your mirror (which happens faster if it’s hot, so you can leave the pitch lap in hot water to heat it up and speed up pressing). Then you take your mirror, put it on your tool, and push it back and forth without applying any downwards pressure.https://hill.pictures/mirror_polishing/4310523-8-mirror-polishing/Tue, 30 Jan 2024 17:11:15 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4310523-8-mirror-polishing/Unable to find image IMG_20240127_141903995_1_1.jpg Unable to find image IMG_20240127_153114171_HDR_1.jpg After all that setup, actually polishing a mirror is surprisingly simple. First you put your mirror on your tool and apply pressure so the pitch flows and takes the shape of your mirror (which happens faster if it’s hot, so you can leave the pitch lap in hot water to heat it up and speed up pressing). Then you take your mirror, put it on your tool, and push it back and forth without applying any downwards pressure.https://hill.pictures/leavitt/buildingblog/4286113-8-mirror-polishing/Fri, 26 Jan 2024 17:16:15 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4286113-8-mirror-polishing/I’m making a tool called a pitch lap to grind an 8" mirror. Previously, I discovered the best way to find dental stone is a dentist, and made a yellow plaster disk. Pitch lap step 2: Pour the pitch! Pitch is a weird material. It’s a liquid so viscous it looks like a solid. At high temperature it’ll pour like honey, at low temperature it’ll act solid but very very slowly flow.https://hill.pictures/mirror_polishing/4286113-8-mirror-polishing/Fri, 26 Jan 2024 17:16:15 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4286113-8-mirror-polishing/Unable to find image IMG_20231216_141319656_HDR_1.jpg Unable to find image image.png Unable to find image image.png Unable to find image image.png I’m making a tool called a pitch lap to grind an 8" mirror. Previously, I discovered the best way to find dental stone is a dentist, and made a yellow plaster disk. Pitch lap step 2: Pour the pitch! Pitch is a weird material. It’s a liquid so viscous it looks like a solid.https://hill.pictures/leavitt/buildingblog/3793120-8-mirror-polishing/Fri, 26 Jan 2024 05:20:59 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/3793120-8-mirror-polishing/Previously, @Beasmeeply generously donated me an 8" mirror blank, kick-starting an attempt to finish grinding it and make an 8" telescope. There are four stages of mirror grinding, so to figure out which step I needed to start with, I put the mirror into a Foucault mirror tester, and it gave a smooth-ish image, telling me BeasMeeply had gotten through the first two stages of mirror making, rough and fine grinding, and it was ready to polish.https://hill.pictures/mirror_polishing/3793120-8-mirror-polishing/Fri, 26 Jan 2024 05:20:59 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/3793120-8-mirror-polishing/Unable to find image IMG_20231202_150448568_HDR_1.jpg Unable to find image IMG_20231207_160216875_1.jpg Unable to find image IMG_20231207_162328078_1.jpg Unable to find image IMG_20231207_170016712_1.jpg Previously, @Beasmeeply generously donated me an 8" mirror blank, kick-starting an attempt to finish grinding it and make an 8" telescope. There are four stages of mirror grinding, so to figure out which step I needed to start with, I put the mirror into a Foucault mirror tester, and it gave a smooth-ish image, telling me BeasMeeply had gotten through the first two stages of mirror making, rough and fine grinding, and it was ready to polish.https://hill.pictures/leavitt/buildingblog/4238338-it-s-mirror-time/Sun, 21 Jan 2024 05:10:38 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/4238338-it-s-mirror-time/Finally finished making a pitch lap for @BeasMeeply’s mirror! Yahoo! Now I can start polishing… as soon as I get some cerium oxide to polish with.https://hill.pictures/mirror_polishing/4238338-it-s-mirror-time/Sun, 21 Jan 2024 05:10:38 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/4238338-it-s-mirror-time/Finally finished making a pitch lap for @BeasMeeply’s mirror! Yahoo! Now I can start polishing… as soon as I get some cerium oxide to polish with.https://hill.pictures/hadley/buildingblog/4209942-half-moon/Thu, 18 Jan 2024 06:08:43 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/4209942-half-moon/A quick moon pic from my 3D printed telescope and phone cam. Some out of focus tree branches snuck into the top and traced some faint dark lines!https://hill.pictures/leavitt/unfinished_motorized_mount/4177281-my-gearbox-finally-h/Sun, 14 Jan 2024 23:09:28 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/unfinished_motorized_mount/4177281-my-gearbox-finally-h/This is going to turn the turntable that my telescope will sit onhttps://hill.pictures/leavitt/unfinished_motorized_mount/4162869-gearbox-has-some-dec/Sat, 13 Jan 2024 05:54:02 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/unfinished_motorized_mount/4162869-gearbox-has-some-dec/I’ll print out a prototype and see if it holds everything the way I want it to. Question I still need to answer: how do I stop the axles from fall outhttps://hill.pictures/leavitt/unfinished_motorized_mount/4159930-gearbox-design-going/Fri, 12 Jan 2024 23:19:36 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/unfinished_motorized_mount/4159930-gearbox-design-going/I don’t know how to design a sketch in one document (for say a stepper motor mount plate) then import it into a different document in a different location (for, say, mounting that stepper in a different place)https://hill.pictures/leavitt/unfinished_motorized_mount/4157379-first-gearbox-test/Fri, 12 Jan 2024 19:00:14 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/unfinished_motorized_mount/4157379-first-gearbox-test/Looks like the belts and pulleys I got fit! Now to design the gearbox and 3D print it so my telescope can move very small amounts accuratelyhttps://hill.pictures/meniscus12/draping/4077674-the-jan-2024-telesco/Thu, 04 Jan 2024 19:18:07 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/4077674-the-jan-2024-telesco/I have many projects in mind for telescope upgrades. Since the last list I’ve completed one and added one. Here’s what I want to do this year telescope wise: #1: Sliced Pifinder (complete!) Complete! I built a Pifinder for 1/5 of the list price by using a different cheaper camera, secondhand older pi and battery pack, and printing and soldering parts myself. It’s been very helpful when it works, and let me take pictures of M33 even without seeing it!https://hill.pictures/hadley/buildingblog/4062839-observing-amongst-th/Wed, 03 Jan 2024 04:30:22 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/4062839-observing-amongst-th/I drove out to what Google maps said was a park and then saw a sign saying “state property no trespassing” and a second sign saying “don’t steal road salt or gravel from here, if we catch you you’ll be prosecuted”. I guess that’s what some silly rural fellows get up to in their free time? So I parked right in front of the entrance off the side of the road, since it was pretty dark.https://hill.pictures/hadley/buildingblog/4049969-the-galaxies-are-ali/Tue, 02 Jan 2024 00:11:06 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/4049969-the-galaxies-are-ali/This is the best photo I’ve made of the Andromeda galaxy! It’s my second time stacking pictures to bring out faint details. You’re looking at 20 phone pics taken through my 3D printed telescope, each 1/2s exposure so the Earth didn’t rotate as much during the photo and smear the stars. I tried the program deepskystacker, but it failed to stack my pictures (maybe my phone camera’s pics had too much noise?https://hill.pictures/hadley/buildingblog/4016831-the-stars-are-aligne/Fri, 29 Dec 2023 21:18:14 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/4016831-the-stars-are-aligne/BEHOLD, MY FIRST STACKED ASTROPHOTOGRAPHY IMAGE! This combines 20 1/2sec exposures taken with my phone through my 3D printed 4.5" telescope. You can see stars down to magnitude 12!! This is so cool. Turns out I didn’t see a galaxy in my photos because… I was looking at photos of a non-galaxy. This is the ring nebula, M57. Oops.https://hill.pictures/hadley/buildingblog/4014863-the-stars-are-not-al/Fri, 29 Dec 2023 17:50:51 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/4014863-the-stars-are-not-al/I took many 1/2s exposures of the galaxy M33 but it wasn’t visible. I’m trying to combine them in python to see if together it can simulate a long exposure. It’s not going too well (The lines are from stars moving as the earth rotates!)https://hill.pictures/meniscus12/draping/3877914-cracked-a-black-hole/Sat, 16 Dec 2023 00:40:11 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/3877914-cracked-a-black-hole/Poured some cement into my CNCed mold! Very fitting that my experimental telescope making technique involves a black hole I noticed my mold had warped before putting cement on it - maybe from the polyurethane spray I used, or from waiting a month in between cncing and pouring? I put some weights on it because of the warping, walked away… And the next day I found my wood split down the middle of a boundary between planks.https://hill.pictures/hadley/buildingblog/3851013-those-galaxies-are-j/Wed, 13 Dec 2023 05:35:50 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/3851013-those-galaxies-are-j/There’s a galaxy (named M33) in most of this picture but it’s so faint I couldn’t see it by eye or by camera :( The pifinder helped me find this place, so I took like 30 exposures in the hopes that I can stack them and see ithttps://hill.pictures/leavitt/unfinished_motorized_mount/3840591-grabbing-gears/Tue, 12 Dec 2023 19:22:32 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/unfinished_motorized_mount/3840591-grabbing-gears/I found a design by d.revan to motorize a telescope using GT2 timing belts and it’s cool. He uses: GT2 belts and pulleys instead of gears 608-2RS skateboard bearings to let the shafts spin (smart!) a giant mega printed gear attached to wood for the final gear stage 4:1, 4:1, then 15:1 gear stages …but I tried seeing how much the parts would be on AliExpress, and it was surprisingly hard to find gears with the right 8mm bore and wider than normal 10mm belt width.https://hill.pictures/hadley/pifinder/3818310-oops-pifinder-actua/Sun, 10 Dec 2023 17:07:33 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/3818310-oops-pifinder-actua/Oops. NOW my Sliced PiFinder is done. The original PiFinder uses a $50 USB GPS module. To avoid spending $50, I wrote some code to fake a GPS. Eventually the dev brickbots switched PiFinders to a $10 solderable GPS module that uses UART instead of USB, and $10 felt reasonable, so I bought one and soldered it in. I thought I was done and that all I had to do was edit the software to remove my fake GPS code and use the regular GPS code!https://hill.pictures/hadley/pifinder/3810526-pifinder-complete/Sat, 09 Dec 2023 20:13:06 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/3810526-pifinder-complete/I’m building the Sliced PiFinder, a device to help my telescope find things! Previously, I tried using a cheaper IMU but gave up and bought a $30 fancy chip. Originally I didn’t want to buy a $50 GPS USB stick but the PiFinder creator found a $10 solderable GPS unit for a v2, so I bought one and soldered it in. After soldering in the GPS chip, dubiously electrical taping it in place, dropping it and cracking my 3D printed parts, printing new parts, using a soldering iron to remove heat inserts out of the old parts so I can place them into the new parts, printing the case, discovering the case wasn’t designed for my battery and blocks access to the on/off switch and USB ports, melting holes in case with soldering iron, putting on a cover plate over the screen and LEDs… I finally put it on my telescope!https://hill.pictures/hadley/pifinder/3741817-pifinder-perils/Mon, 04 Dec 2023 15:29:08 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/3741817-pifinder-perils/I’m building a PiFinder! It uses a camera to take pictures of the sky, connected to a raspberry pi which uses a database of stars to tell you where in the sky your telescope is pointing. But a PiFinder is $550 new. A stock pifinder uses the newest and most expensive options for pis and cameras, and when I looked at the parts list, I thought: I can build something similar for a fifth of the price!https://hill.pictures/hadley/pifinder/3661910-pifinder-is-almost-p/Sun, 26 Nov 2023 01:17:31 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/3661910-pifinder-is-almost-p/The pifinder is a tool to help you aim a telescope. It uses a camera to take pictures of the sky, connected to a raspberry pi which uses a database of stars to tell you where in the sky your telescope is pointing. Then, if you want to find a specific object, it tells you what direction to move your telescope in. I’m building a janky pifinder with some nonstandard parts: instead of a $60 raspi 4 and $50 HQ camera and $25 lens and $30 IMU, I’m using a $10 lens, a secondhand raspi 3, and a cheap “pi camera module v1” from 2013 that was attached to the raspi, and a $20 IMU with unpronounceable name I found lying around in a drawer of sensors.https://hill.pictures/hadley/pifinder/3638072-maybe-this-camera-wi/Thu, 23 Nov 2023 17:42:35 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/3638072-maybe-this-camera-wi/Pifinder update: the new $33 camera arrived! But it’s slightly bigger than my previous camera, so I had to design a new part to hold it. While the pifinder was designed with M2.5 screws, this camera only accepts smaller M2 screws. I had to go to the hardware store yet again. The pifinder is designed for a raspberry pi HQ camera ($50). Originally instead I wanted to use a pi camera module V1 ($10, from 2013) because I recycled it from another project, but it didn’t work too well.https://hill.pictures/meniscus12/draping/3615280-circle-cutting-fail/Tue, 21 Nov 2023 19:26:27 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/3615280-circle-cutting-fail/The scoring tool cut a circle fine, but then the next step was supposed to be “press it from the rear side and the crack will deepen”, and it just… Didn’t. Maybe this glass is just too thick? I still have half my countertop left, I need a new way to cut 1/2" glasshttps://hill.pictures/hadley/buildingblog/3484395-my-first-orion-nebul/Sat, 11 Nov 2023 04:00:21 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/3484395-my-first-orion-nebul/The first picture is at 36x zoom, the second one at 150x zoom. The more zoomed in one is fainter because the same light is spread across more area, but you can see the four trapezium stars as four separate streaks! This was a very frustrating night for photography because finding things in a big sky is hard. Light pollution made it hard to see M31, I couldn’t find M33, and then finally clouds rolled in and it became a race against time to photograph the Orion nebula M42.https://hill.pictures/meniscus12/draping/3286208-a-friendly-older-guy/Tue, 24 Oct 2023 17:57:56 +0000hillexed@email.com (hillexed)https://hill.pictures/meniscus12/draping/3286208-a-friendly-older-guy/I’m so excited. Making really big really thin meniscus mirrors has officially gone from cool idea to possiblehttps://hill.pictures/mirror_polishing/3286208-a-friendly-older-guy/Tue, 24 Oct 2023 17:57:56 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/3286208-a-friendly-older-guy/Unable to find image IMG_20231024_132057346_HDR_1.jpg Unable to find image IMG_20231024_134541085_HDR_1.jpg I’m so excited. Making really big really thin meniscus mirrors has officially gone from cool idea to possiblehttps://hill.pictures/leavitt/buildingblog/secondary/3272414-adjusting-for-mirror/Mon, 23 Oct 2023 14:55:28 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/secondary/3272414-adjusting-for-mirror/I got a mirror that’s 2.3 inches wide. However, several weeks ago, I printed a mirror holder that was designed to fit a mirror 2.46 inches wide. Sure, I could just use the bigger holder, but the bigger the secondary holder the more light it blocks from reaching your mirror. Is it worth a smaller secondary mirror holder that will block half a square inch less light? Yes, I decided. So I opened up the model and slightly scaled it down.https://hill.pictures/leavitt/buildingblog/secondary/3233670-secondary-mirror-get/Thu, 19 Oct 2023 20:19:03 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/secondary/3233670-secondary-mirror-get/Visiting family in another city, and turns out there’s an astronomy store named La Maison De L’Astronomie (The Astronomy House)! I called them up to see if they had some secondary mirrors in stock… And they did! They had so many big telescopes, way more small refractors than I was expecting, a huge cabinet of binoculars, and some absolutely massive tripod mounts. The bbastro calculator says the most optimal uniform illumination secondary mirror size is 62.https://hill.pictures/hadley/buildingblog/3217754-m13-the-great-hercu/Wed, 18 Oct 2023 14:08:06 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/3217754-m13-the-great-hercu/I found this with the help of an amateur with a huge telescope and laser pointer so bright it looked like a line pointing into the sky. Looked like a dim circular smudge to the eye. Picture taken with the 25mm eyepiece, so I bet I could get an even better picture through the more zoomed in 6mmhttps://hill.pictures/hadley/buildingblog/3175200-annular-eclipse-toda/Sat, 14 Oct 2023 14:21:02 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/3175200-annular-eclipse-toda/Reminder to North and South Americans, there’s an eclipse today! https://www.timeanddate.com/eclipse/in/usa?iso=20231014 DON’T LOOK AT THE SUN WITHOUT SPECIAL ECLIPSE GLASSES, EVEN DURING A PARTIAL ECLIPSE! If you don’t have one, take a piece of paper, punch a hole in it, and look at the shadow. Trees or colanders with many holes will make very cool shadows!https://hill.pictures/hadley/buildingblog/3137720-i-got-the-ring-nebul/Wed, 11 Oct 2023 15:22:43 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/3137720-i-got-the-ring-nebul/YEAHHHHH FINALLY IT’S SO SMALL FINDERSCOPE HELPEDhttps://hill.pictures/hadley/buildingblog/3120558-telescope-update/Mon, 09 Oct 2023 18:13:12 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/3120558-telescope-update/I put a telescope on my telescopehttps://hill.pictures/leavitt/buildingblog/3105482-i-tested-my-donated/Sun, 08 Oct 2023 15:06:35 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/3105482-i-tested-my-donated/WOW! That’s a good mirror! Previously, @BeasMeeply graciously donated me an 8" mirror. The problem: I don’t know what stage of mirror making I have to do. So I talked to a local astronomy club. I got to use a spherometer to measure the curve - same curvature all around, accurate to within 0.0002 inches. I put it in a foucalt tester, and after lots of help and fiddling I got some pictures of the result!https://hill.pictures/mirror_polishing/3105482-i-tested-my-donated/Sun, 08 Oct 2023 15:06:35 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/3105482-i-tested-my-donated/Unable to find image IMG_20231007_152202849_smol.png WOW! That’s a good mirror! Previously, @BeasMeeply graciously donated me an 8" mirror. The problem: I don’t know what stage of mirror making I have to do. So I talked to a local astronomy club. I got to use a spherometer to measure the curve - same curvature all around, accurate to within 0.0002 inches. I put it in a foucalt tester, and after lots of help and fiddling I got some pictures of the result!https://hill.pictures/leavitt/buildingblog/3033178-printing-for-the-8/Sun, 01 Oct 2023 20:51:59 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/3033178-printing-for-the-8/I’m not the first person to build a Hadley 3D printed telescope and then want something bigger. There are two 3D printed 8" telescope designs: the “Bradley” is only available by DMing someone on a discord server, and it’s designed for a printer big enough to fit an 8" circle. I don’t have a printer that big! Thankfully, there’s also the “Leavitt”, a design which splits 8" circles into three pieces so they can fit on a normal Ender-sized printer.https://hill.pictures/mirror_polishing/3033178-printing-for-the-8/Sun, 01 Oct 2023 20:51:59 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/3033178-printing-for-the-8/I’m not the first person to build a Hadley 3D printed telescope and then want something bigger. There are two 3D printed 8" telescope designs: the “Bradley” is only available by DMing someone on a discord server, and it’s designed for a printer big enough to fit an 8" circle. I don’t have a printer that big! Thankfully, there’s also the “Leavitt”, a design which splits 8" circles into three pieces so they can fit on a normal Ender-sized printer.https://hill.pictures/leavitt/buildingblog/2905637-an-incredibly-genero/Thu, 28 Sep 2023 15:12:15 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/buildingblog/2905637-an-incredibly-genero/A while ago I was musing about ways to get better space pics, and @BeasMeeply incredibly generously offered to donate an 8" blank sitting in his closet for 10 years if I paid for shipping! Thank you so much! I’ve got it now and it looks incredibly clear. He also sent a metal 1.25" focuser, which was an extra addition I wasn’t expecting. It’s like I was standing on the edge of an abyss deciding whether not to jump in, and then someone threw a mirror at my back.https://hill.pictures/mirror_polishing/2905637-an-incredibly-genero/Thu, 28 Sep 2023 15:12:15 +0000hillexed@email.com (hillexed)https://hill.pictures/mirror_polishing/2905637-an-incredibly-genero/Unable to find image IMG_20230919_223643192_1.jpg A while ago I was musing about ways to get better space pics, and @BeasMeeply incredibly generously offered to donate an 8" blank sitting in his closet for 10 years if I paid for shipping! Thank you so much! I’ve got it now and it looks incredibly clear. He also sent a metal 1.25" focuser, which was an extra addition I wasn’t expecting. It’s like I was standing on the edge of an abyss deciding whether not to jump in, and then someone threw a mirror at my back.https://hill.pictures/hadley/buildingblog/2905620-andromeda-galaxy-cor/Wed, 20 Sep 2023 14:36:37 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2905620-andromeda-galaxy-cor/I got to see it with my own eyes for the first time!! It looked like a gray oval-ish but slightly pointy smudge. But it’s a cool smudge in the sky!! This is a phone pic with a 2s exposure and ISO cranked up to it’s max, 3200. The rainbow snow is random noise from my sensor magnified by turning the sensitivity up very high. You can even see M32 as a slightly fuzzy star almost directly above Andromeda’s core!https://hill.pictures/hadley/buildingblog/2885861-dumb-telescope-idea/Mon, 18 Sep 2023 17:27:56 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2885861-dumb-telescope-idea/I’ve been thinking about https://www.space.com/liquid-telescope-construction-in-space-ax-1 . I wonder if you could take a circular baking tray, spin it on a pottery wheel, and then pour SLA 3D printing resin into it so the resin would form a liquid mirror, then shine UV light on it to cure it and make a telescope mirrorhttps://hill.pictures/hadley/pifinder/2801657-i-think-i-figured-ou/Mon, 11 Sep 2023 04:28:35 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/2801657-i-think-i-figured-ou/The code’s open source, so I looked through it. Turns out every time it tries to draw a map of the sky, it loops through every single star in the sky down to magnitude 7.5. Every frame. Sigh At least it’s open source, so I can probably add some caching and massively speed it up.https://hill.pictures/hadley/pifinder/2789557-oh-yeah-i-m-making/Sun, 10 Sep 2023 01:01:27 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/2789557-oh-yeah-i-m-making/The sky is too big. I went out telescoping looking for M13 and there were too many stars and it’s too big and I don’t know where I’m aimed. When you’re so zoomed in, there’s so many stars you don’t know where you are or where to look. Enter the pifinder! I’m going to make one. I went to my local makerspace, known for having too many donated bits and bobs they actively try to get rid of (what a wonderful problem to have).https://hill.pictures/hadley/pifinder/2753355-possible-telescope-u/Wed, 06 Sep 2023 20:39:46 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pifinder/2753355-possible-telescope-u/My telescope is pretty good, but now that I have one I’ve been thinking about how to get even better. Here’s what I’ve been thinking about: #1: Bigger telescope. Bigger telescopes with bigger mirrors both capture more light and allow you to resolve tinier details. I saw someone made a “Leavitt” telescope, also 3D printed, designed to fit an 8" mirror! My telescope has a 4.5" mirror right now. It cost $30.https://hill.pictures/hadley/buildingblog/2683678-jupiter-belts-jupite/Thu, 31 Aug 2023 14:52:05 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2683678-jupiter-belts-jupite/THE NEW TELESCOPE MIRROR IS GREAT BEST $20 I’VE SPENThttps://hill.pictures/hadley/buildingblog/2641780-uploaded-my-telescop/Sun, 27 Aug 2023 18:43:33 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2641780-uploaded-my-telescop/Now anyone can have a sturdy 3D printed telescope! https://www.printables.com/model/565412-hill-mount-for-hadley-telescopehttps://hill.pictures/hadley/buildingblog/2611104-on-the-night-of-the/Thu, 24 Aug 2023 23:28:28 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2611104-on-the-night-of-the/For the record, past me was wrong. That’s not the ring nebula. There aren’t two bright stars aligned like that near the ring nebula. But that’s the prettiest Jupiter I’ve ever taken! (Why is there a double saturn? I know why now!)https://hill.pictures/hadley/buildingblog/2573607-attacking-vibration/Tue, 22 Aug 2023 16:56:49 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2573607-attacking-vibration/Telescope mount v3 is pretty good, but it still wobbles slightly. If I touch or move the telescope, it wobbles a bit before settling down in 2-3 seconds. Before it settles down, Saturn turns into two images of Saturn next to each other. I can use that picture and do the math to see how much it's wobbling:https://www.timeanddate.com/astronomy/planets/distance says Saturn is 18.96" right now. That's a second of arc, 1/60 of a minute of arc, which is 1/60 of a degree.https://hill.pictures/hadley/buildingblog/2554147-oh-my-god-there-s-so/Sun, 20 Aug 2023 06:27:52 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2554147-oh-my-god-there-s-so/I drove a few hours to visit friends and a bortle 4 sky. wow there were so many stars. You could barely make out an arc slightly lighter in the sky than the rest of it! The Milky Way! Through a telescope, there were much more stars than before and they just kept going and going if you moved the telescope. Saw the plediades too wow many bright stars near each otherhttps://hill.pictures/hadley/buildingblog/2498706-brightnesses-are-cur/Tue, 15 Aug 2023 20:46:47 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2498706-brightnesses-are-cur/Today I learned that astronomers measure star brightnesses in the modern AB system, using (logarithmic) units of Janskys, where one Jansky is 10−26 W⋅m−2⋅Hz−1. Why is there the extremely cursed Hz−1? Hz is already s−1. Why is it like that. Astronomers, why is it like that. s−1−1 is just seconds If you cancel all the units, you get… 1 Jy = 10−26 kg m2 s−3m−2 s−1−1 = 10-26 kg s−2. …so we measure starlight in the same units as surface tension.https://hill.pictures/hadley/buildingblog/2463232-which-3d-model-takes/Sat, 12 Aug 2023 19:02:19 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2463232-which-3d-model-takes/ turns out it’s… click to reveal the first one?? 3D printers fill the inside of objects with really lightweight infill, and it's so light compared to 100% filled walls that it takes both less time and ends up being less weight than the fancy truss on the right. Which sucks because I spent such a long time designing that fancy truss only to be outdone by a brick.https://hill.pictures/hadley/buildingblog/2457780-i-saw-a-meteor/Sat, 12 Aug 2023 04:30:41 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2457780-i-saw-a-meteor/I heard there was a meteor shower tomorrow! So naturally I went out today to see it. First I treated it like any other target and tried to find a good gap in the trees to see Perseus, but then I read online that meteors appear in the full sky, not just at the radiant. So I lay down on the sidewalk, and 30 minutes later… zoop! The meteor was super underwhelming compared to the time I spent waiting.https://hill.pictures/hadley/buildingblog/2394733-only-bad-space-today/Mon, 07 Aug 2023 14:17:42 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2394733-only-bad-space-today/Everything was very blurry today and I kept wondering why focusing didn’t seem to fix it before realizing it was cloudy. My custom Pico Bluetooth picture taking button worked great though!https://hill.pictures/hadley/pictaker/pico-pictaker/Fri, 04 Aug 2023 02:25:25 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/pictaker/pico-pictaker/It all started with an idea for better telescope images. I take photos using my phone. My telescope shakes when I press the capture button. I have a raspberry pi pico W, which recently added bluetooth. I wonder if I can connect the pico to my phone as a bluetooth device so I could press a button on the pico and remotely take a snapshot. Bluetooth is a nightmare the C++ standard is a mess of inscrutable acronyms.https://hill.pictures/hadley/buildingblog/2349212-an-idea-for-better-i/Thu, 03 Aug 2023 22:59:32 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2349212-an-idea-for-better-i/I take photos using my phone. My telescope shakes when I press the capture button. I have a raspberry pi pico W, which recently added bluetooth. I wonder if I can connect the pico to my phone as a bluetooth device so I could press a button on the pico and remotely take a snapshothttps://hill.pictures/hadley/buildingblog/2322892-welcome-welcome-ne/Wed, 02 Aug 2023 18:43:00 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2322892-welcome-welcome-ne/I got the Andromeda galaxy!!! Aiming the telescope was a nightmare. “I’ll use a star app to aim!” I thought. I tried downloading Stellarium, it complained about a Google Play error. I downloaded SkEye, and it had some weird gyro issues because it expected the phone to be pointing in the same direction as the telescope, but I use my phone camera to take pics so it was mounted sideways looking at the telescope’s eyepiece.https://hill.pictures/hadley/buildingblog/2267354-pictures-from-my-3d/Sat, 29 Jul 2023 18:12:59 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2267354-pictures-from-my-3d/I finally finished Hill Mount v3, so I put it to the test. I got the clearest phone-cam Saturn I’ve ever seen! Wobbles still exist if you touch the telescope, but the wobbles are much smaller now and go away if I wait a few seconds or use a short exposure time. Before the wobbles settle down, if you take a picture with a big exposure time, the wobbles cause the image to have two Saturns.https://hill.pictures/hadley/buildingblog/2257267-telescope-mount-v3/Sat, 29 Jul 2023 01:19:05 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2257267-telescope-mount-v3/This mount is my stiffest one yet! Changes from last time: uses steel EMT instead of wooden dowels, for extra stiffness flat sides so you can see the degree markings deeper and more visible degree markings It feels pretty darn stiff! Unfortunately, tapping the side still makes the telescope wobble. It’s definitely much less wobble than before, though. Maybe it’ll be enough for clear pictures!https://hill.pictures/hadley/buildingblog/2247464-maybe-it-wasn-t-the/Fri, 28 Jul 2023 17:22:10 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2247464-maybe-it-wasn-t-the/maybe this orange filament just likes to warp. Anyway, all parts printed!https://hill.pictures/hadley/buildingblog/2232937-telescope-mount-v3-i/Thu, 27 Jul 2023 18:35:50 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2232937-telescope-mount-v3-i/Just need one more big part to print!https://hill.pictures/hadley/buildingblog/2216684-telescope-mount-v3-i/Wed, 26 Jul 2023 18:47:58 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2216684-telescope-mount-v3-i/comment “safe printing mx mount” to lend it your energyhttps://hill.pictures/hadley/buildingblog/2216246-here-s-a-cool-cutawa/Wed, 26 Jul 2023 18:21:33 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2216246-here-s-a-cool-cutawa/Here’s a cutaway view of my telescope’s 3D printed bases to hold rods in place. The rods go into the giant cylinders, but how do you stop them from slipping out? Insert a nut in on one side of the hole, and then screw it in from the other side. The cut in the top means the entire piece bends to hold the rod in tightly! This is so annoying to design because my rods are so close together you need to make sure that the cutaway for the nuts and screws don’t accidentally cut a hole in the wall of the places where the rods go.https://hill.pictures/hadley/buildingblog/2127715-gas-giants-wooden-w/Thu, 20 Jul 2023 17:07:03 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2127715-gas-giants-wooden-w/I took my new wooden-dowel telescope mount for a spin, and got pictures of Jupiter and Saturn with my high-power eyepiece! I took many pictures, and a few videos. I also figured out how to control the shutter speed on my phone’s camera, and got many photos at 1/40s shutter speed. Using a smaller shutter speed takes the planets from blinding white blurs to circular colored blurs, I assume because it lets in less light.https://hill.pictures/hadley/buildingblog/2063847-built-part-of-it/Sat, 15 Jul 2023 20:42:24 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2063847-built-part-of-it/It’s still sturdy, but wobbles when I hit it. I think it might be the springiness of the wooden dowels that’s causing the motion. I could try adding two more struts and seeing if it works but I don’t really want to. It’s also very colorful now. Time for EMT, I guess!https://hill.pictures/hadley/buildingblog/2059942-another-way-forward/Sat, 15 Jul 2023 15:31:44 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/2059942-another-way-forward/Last telescope update I finished mount v2 and was stuck because it wobbled. One way to try again is to make the rods out of metal EMT instead of wooden dowels. I bought a hacksaw and spent a while hacksawing my EMT to the right length before learning there were specific pipe cutting tools that were far easier to use. Oops! I’ll also need to redesign my mount to use the larger 0.https://hill.pictures/hadley/buildingblog/1996909-a-new-rod-challenger/Tue, 11 Jul 2023 15:49:23 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1996909-a-new-rod-challenger/Update: I’ve learned about the existence of EMT conduit, which is steel so it’s much stiffer, cuttable with a handsaw, and most importantly way cheaper than the aluminum tubes I bought before! The downside is it’s sized in nominal diameter, which means lying. The size “1/2 in” has an outer diameter of 0.706 in. But I’ve faced nominal diameter before and this time I’m prepared. Let’s try this.https://hill.pictures/hadley/buildingblog/1892310-telescope-mount-v2/Wed, 05 Jul 2023 21:50:20 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1892310-telescope-mount-v2/It didn’t work. The main type of wiggling I was trying to stop is the top part twisting around the z axis compared to the bottom part. This new mount stood up well, but if I placed the telescope on the mount and gave it a sideways nudge, the telescope would wiggle from side to side at a period of about 1/4 s. It does seem less wobbly than my previous square mount, but it’s still pretty wobbly.https://hill.pictures/hadley/buildingblog/1886141-telescope-mount-v2-c/Wed, 05 Jul 2023 17:22:59 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1886141-telescope-mount-v2-c/Starting to build telescope mount v2! I’m using 0.5in rods, and v1 had holes 0.52in wide. This one has holes 0.51in wide, and that was a mistake, it made getting the rods in there so much more annoying.https://hill.pictures/hadley/buildingblog/1854050-triforce-of-space/Tue, 04 Jul 2023 01:55:19 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1854050-triforce-of-space/Telescope mount v2 has 3/4 pieces printed! The pretty colors are because I ran out of filament twicehttps://hill.pictures/hadley/buildingblog/1776602-it-didn-t-work/Sat, 01 Jul 2023 20:41:07 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1776602-it-didn-t-work/I put everything together for version 1 of my telescope truss mount. It stands! It was also an inch too wide for the telescope to properly rest on it. I had to rotate it the wrong way so it could fit on the stand for the picture. Aargh. Some of the clamps did grip the rods well, some of the clamps didn’t. The base did feel pretty solid, but the top part is still pretty wobbly after full assembly.https://hill.pictures/hadley/buildingblog/1775037-my-telescope-mount-p/Wed, 28 Jun 2023 18:23:59 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1775037-my-telescope-mount-p/Came out with some blobs and very stringy, which isn’t good, but they came off with some pliers. Time to go cut my dowels to size and see if it all fitshttps://hill.pictures/hadley/buildingblog/1756227-designing-a-new-moun/Sun, 25 Jun 2023 20:53:32 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1756227-designing-a-new-moun/My 3D printed telescope has a problem: it’s very wobbly. That means it’s hard to point the telescope at a planet and have it stay pointed at the planet. It also means I can’t focus it well, or take good pictures through my phone. The telescope itself is fine, but the mount is the problem. There’s a 3D printed mount included in the files with the telescope, and I built that 3D printed mount (after trial and error and discovering pipe sizes are a lie ).https://hill.pictures/hadley/buildingblog/1597469-moon-nyoom/Sat, 03 Jun 2023 16:42:31 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1597469-moon-nyoom/With all those upgrades, I was able to mount my phone to my telescope. Recently, the moon finally reached the right phase for it to be visible, so I got great shots of the moon! With my 6mm high power lens, the moon was super duper detailed. And I realized something amazing: the moon was moving. I was so zoomed in I could see the rotation of the earth! That’s incredible!https://hill.pictures/hadley/buildingblog/1567101-telescope-upgrade-2/Thu, 01 Jun 2023 15:05:23 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1567101-telescope-upgrade-2/(Part 3 of my adventures with my 3D printed telescope! Previous part) I tried adding 3 upgrades, but only two of them worked. Check out an amazing moon photo below! Upgrades My mount is very wobbly. To reduce the wobble I had two ideas: first, place wooden dowels along the diagonals of the sides to make the mount more rigid, and second, print an openocular.com phone holder so I didn’t have to touch the telescope to take pictures with my phone and wobble it.https://hill.pictures/hadley/buildingblog/1516194-telescope-upgrade-1/Fri, 26 May 2023 21:59:57 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1516194-telescope-upgrade-1/(Part 2 of my adventures with my 3D printed telescope!) I printed a collimation helper and a basket! The collimation helper helped me find out that I thought I was collimated, but was actually misaligned. With proper collimation, I went out again and took this new picture of Venus. To the eye, collimation didn’t seem like it did anything, because my telescope and its mount was just so wobbly it looked the same to the eye as before.https://hill.pictures/hadley/buildingblog/1491006-one-imposter-remains/Sat, 13 May 2023 05:21:48 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/buildingblog/1491006-one-imposter-remains/this entire journey started because I could only find 3-packs of aluminum pipes and needed a fourth. What a story this frame hashttps://hill.pictures/blog/pipenonsense/Wed, 10 May 2023 18:39:09 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/pipenonsense/I have a 1/2" diameter hole. I want to put a pipe inside the hole. What size PVC pipe fits into a 1/2" hole? Did you guess 1/2" pipe? WRONG. “1/2 inch pipe” isn’t half an inch big on the outside. It’s closer to 7/8". You might think “ah so the 1/2” refers to the inner diameter". Wrong. The inner diameter of 1/2" PVC pipe is legally required to be 0.https://hill.pictures/blog/573-ionicliquids/Tue, 25 Apr 2023 14:38:14 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/573-ionicliquids/Today I learned liquids don’t exist in space. It’s either gas or solid because apparently liquids only exist when you have a ton of force squishing atoms together and forcing them to intersct and normally that’s air smashing into things at high speed. Crazy. Space whales won’t know what liquids are Later that day… I found https://www.nasa.gov/ames/flute ! They want to use reflective liquids to make perfect parabola shapes for mirrors!https://hill.pictures/posts/post-3/Wed, 15 Mar 2023 11:00:00 -0700hillexed@email.com (hillexed)https://hill.pictures/posts/post-3/Occaecat aliqua consequat laborum ut ex aute aliqua culpa quis irure esse magna dolore quis. Proident fugiat labore eu laboris officia Lorem enim. Ipsum occaecat cillum ut tempor id sint aliqua incididunt nisi incididunt reprehenderit. Voluptate ad minim sint est aute aliquip esse occaecat tempor officia qui sunt. Aute ex ipsum id ut in est velit est laborum incididunt. Aliqua qui id do esse sunt eiusmod id deserunt eu nostrud aute sit ipsum.https://hill.pictures/posts/post-2/Wed, 15 Feb 2023 10:00:00 -0700hillexed@email.com (hillexed)https://hill.pictures/posts/post-2/Anim eiusmod irure incididunt sint cupidatat. Incididunt irure irure irure nisi ipsum do ut quis fugiat consectetur proident cupidatat incididunt cillum. Dolore voluptate occaecat qui mollit laborum ullamco et. Ipsum laboris officia anim laboris culpa eiusmod ex magna ex cupidatat anim ipsum aute. Mollit aliquip occaecat qui sunt velit ut cupidatat reprehenderit enim sunt laborum. Velit veniam in officia nulla adipisicing ut duis officia. Exercitation voluptate irure in irure tempor mollit Lorem nostrud ad officia.https://hill.pictures/posts/post-1/Sun, 15 Jan 2023 09:00:00 -0700hillexed@email.com (hillexed)https://hill.pictures/posts/post-1/Tempor proident minim aliquip reprehenderit dolor et ad anim Lorem duis sint eiusmod. Labore ut ea duis dolor. Incididunt consectetur proident qui occaecat incididunt do nisi Lorem. Tempor do laborum elit laboris excepteur eiusmod do. Eiusmod nisi excepteur ut amet pariatur adipisicing Lorem. Occaecat nulla excepteur dolore excepteur duis eiusmod ullamco officia anim in voluptate ea occaecat officia. Cillum sint esse velit ea officia minim fugiat. Elit ea esse id aliquip pariatur cupidatat id duis minim incididunt ea ea.https://hill.pictures/blog/6606-this-intro-to-synths/Mon, 12 Dec 2022 22:10:23 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/6606-this-intro-to-synths/This is the 1985 “electronotes builder’s guide and preferred circuits collection” and Bernie Hutchins is advising first time synth makers go buy chemicals at radioshack to etch copper and use a paintbrush to trace out wires manually. It’s so weirdly analog and hands-on compared to the way circuit boards are made today I’m used to, “pay someone else online to do it”https://hill.pictures/blog/572-living-newspapers/Thu, 08 Dec 2022 20:36:09 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/572-living-newspapers/As a tiny part of the New Deal, Hallie Flanagan helped create the Federal Theatre Project in 1935, where the US government funded unemployed actors to make free plays available to all. A big part of those were Living Newspapers: researchers became playwrights and wrote about current events lifted from the headlines to inform people. The very first Living Newspaper was a hilarious tragedy. “Ethiopia” by Arthur Arent was all about how being invaded during the Second Italo-Ethiopian War was ravaging the country.https://hill.pictures/blog/551252mysteryshirt/Tue, 06 Dec 2022 01:12:58 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/551252mysteryshirt/i bought a t-shirt and the store offered a “$3 mystery t-shirt” so i figured cheap t-shirt why not. presumably that was so they could get rid of t-shirts that didn’t sell well it finally arrived… and it’s extremely impressively the exact opposite of my stylehttps://hill.pictures/blog/502613-a-wqalk-in-the-forws/Wed, 30 Nov 2022 20:12:39 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/502613-a-wqalk-in-the-forws/ME: hi drabgon i see your home has many trees DRABGON: contrary to poplar belief we don’t breathe fire NEARBY TREE: don’t believe that liar! I bet it’s just waiting for the right momenthttps://hill.pictures/blog/jwsthopes/Wed, 16 Nov 2022 03:20:08 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/jwsthopes/i hope the rocket goes away properly (note from 2025: the JWST space telescope launched flawlessly!)https://hill.pictures/blog/192722-how-microprocessors/Sat, 12 Nov 2022 18:11:52 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/192722-how-microprocessors/So I’ve been working on trying to make a little Arduino powered synthesizer recently! Turns out it’s hard and sound is complicated and now I’m cursed with knowledge. The only way to get rid of curses is to dilute them, so here’s everything I’ve learned about how to make sound on an Arduino. Speakers A speaker takes some electricity and moves a little flat thing either outwards or inwards depending on the voltage, which pushes on air and makes sound.https://hill.pictures/blog/260450-and-the-days-go-spa/Fri, 11 Nov 2022 03:04:39 +0000hillexed@email.com (hillexed)https://hill.pictures/blog/260450-and-the-days-go-spa/And the days go on and on and onhttps://hill.pictures/hadley/aiming/Mon, 01 Jan 0001 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/aiming/My Hadley has two upgrades that help it aim. Finderscope The first upgrade is an 6x50 finderscope that says “orion” on it. I found it in my local astronomy club’s shelf of spare parts, bought it for $10, and designed a 3D printed adapter for it to fit onto my Hadley. It features integrated crosshairs and helps me aim at planets at a glance! Unable to find image finderscope.jpg Sliced Pifinder The second upgrade is the Sliced PiFinder.https://hill.pictures/hadley/hadley-astigmatism/Mon, 01 Jan 0001 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/hadley/hadley-astigmatism/When I tried to focus my Hadley on mars, I couldn’t see very much. It looked like a blob. When I looked at Saturn, I noticed a sort of double-saturn effect. The Hadley’s default telescope mount was very wobbly. I assumed that the pattern I was seeing of two saturn images was actually one Saturn image vibrating back and forth quickly. Based on this assumption, I designed a much stiffer truss mount.https://hill.pictures/leavitt/mirrorgrinding/Mon, 01 Jan 0001 00:00:00 +0000hillexed@email.com (hillexed)https://hill.pictures/leavitt/mirrorgrinding/(This page is a work in progress!) I dove into the rabbit hole of optical fabrication and made my own mirrors for my 8" Leavitt telescope. When we think of mirrors, we think of mirrors like those on a bathroom wall, which are flat. Telescope mirrors are curved, to focus light to a point. This curvature focuses parallel light rays everywhere on the mirror’s surface to the same place, increasing the amount of light the eye can see when looking through a telescope.