This little 3D printed telescope kickstarted my journey into astronomy. The design is free and open source, and uses 3D printed parts, aluminum tubes, and hardware store nuts and bolts.
It sits on the Hill Mount, a portable and cheap altitude mount I designed that costs around $20. It’s lightweight enough I have walked two miles to a subway stop while carrying it the whole time.
Azimuth is controlled by physically sliding the plastic across the ground. Sure, I could put it on a turntable, but that would make it heavier.
It has a number of upgrades - including an integrated finderscope and a high-tech computerized aiming system I printed and hand-soldered myself.
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 and designed a 3D printed adapter for it to fit onto the telescope. It features integrated crosshairs and helps me line up planets at a glance!
Sliced Pifinder
The second upgrade is the Sliced PiFinder. It’s a targeting computer that permanently lives on my telescope - which is an incredible sentence. We truly live in the future.
The PiFinder is a device that uses a raspberry pi and a camera to take pictures of the sky and compute where in the sky your telescope is aiming, even with high light pollution. Since it knows where the telescope points, you can select a particular galaxy or nebula and it will tell you how to push the telescope to get there.
PiFinders are an open-source project that can also be bought for $500 from the designer. Mine was built for $110 - a mere slice of the cost. The stock PiFinder is designed for a Raspberry Pi 4 using the Raspberry Pi High Quality Camera ($50) with a $50 lens, but I 3D printed and assembled the parts myself, used a scavenged battery pack and previous-generation Raspberry Pi 3 from a defunct project, and a $30 IMX462 camera and $12 lens.
Taking photos on a budget
I like to think of myself as on the cutting edge of cell phone astrophotography. I use a 3D printed clamp to hold my phone up to the eyepiece and take photos using my phone camera. However, tapping the phone button causes vibrations that wobble the telsecope. To fix that, I use a raspberry pi pico microcontroller as a wireless remote shutter. I programmed it to act as a bluetooth mouse and connect to my phone. When I press the built-in button, it moves the mouse to the center of the screen and clicks the “take picture” button. To see pictures this setup has taken, take a look at my Astrophotos page!
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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).
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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.
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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!)
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Huh. I installed the front truss addon, I’m observing now and finally noticed the direction of the wobble. After a transient big vibration period of 3s or so it settles down… and stars look like two points right next to each other instead of a big glob of light. Progress! I looked at a low-altitude object… And the direction of the two stars was up and down. I think I’ve finally defeated side to side wobble only to find my true opponent was altitude wobble
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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.
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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 other
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Jupiter, four Galilean moons, and a blue star!
It could be improved if I was better collimated, but I’m happy I got all 4 of them with the high power eyepiece!
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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.
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