DIY Open-Source Star Tracker Gets You Those Great Night Shots

February 25, 2025 by Donald Papp No comments

What does one do when frustrated at the lack of affordable, open source portable trackers? If you’re [OG-star-tech], you design your own and give it modular features that rival commercial offerings while you’re at it.

What’s a star tracker? It’s a method of determining position based on visible stars, but when it comes to astrophotography the term refers to a sort of hardware-assisted camera holder that helps one capture stable long-exposure images. This is done by moving the camera in such a way as to cancel out the effects of the Earth’s rotation. The result is long-exposure photographs without the stars smearing themselves across the image.

Interested? Learn more about the design by casting an eye over the bill of materials at the GitHub repository, browsing the 3D-printable parts, and maybe check out the assembly guide. If you like what you see, [OG-star-tech] says you should be able to build your own very affordably if you don’t mind 3D printing parts in ASA or ABS. Prefer to buy a kit or an assembled unit? [OG-star-tech] offers them for sale.

Frustration with commercial offerings (or lack thereof) is a powerful motive to design something or contribute to an existing project, and if it leads to more people enjoying taking photos of the night sky and all the wonderful things in it, so much the better.

Amateur Astronomer Images Spy Satellite

September 20, 2024 by Bryan Cockfield 14 Comments

As anyone who’s looked at the sky just before dawn or right after dusk can confirm, for the last seventy years or so there have been all kinds of artificial satellites floating around in low-Earth orbit that are visible to the naked eye. Perhaps the most famous in the last few decades is the International Space Station, but there are all kinds of others up there from amateur radio satellites, the Starlink constellation, satellite TV, and, of course, various spy satellites from a few of the world’s governments. [Felix] seems to have found one and his images of it can be found here.

[Felix] has been taking pictures of the night sky for a while now, including many different satellites. While plenty of satellites publish their paths to enable use, spy satellites aren’t generally public record but are still able to be located nonetheless. He uses a large Dobsonian telescope to resolve the images of several different satellites speculated to be spy satellites, with at least one hosting a synthetic aperture radar (SAR) system. His images are good enough to deduce the size and shape of the antennas used, as well as the size of the solar panels on board.

As far as being concerned about the ramifications of imaging top-secret technology, [Felix] is not too concerned. He states that it’s likely that most rival governments would be able to observe these satellites with much more powerful telescopes that he has, so nothing he has published so far is likely to be a surprise to anyone. Besides, these aren’t exactly hidden away, either; they’re up in the sky for anyone to see. If you want to take a shot at that yourself you can get a Dobsonian-like telescope mostly from parts at Ikea, and use a bit of off-the-shelf electronics to point them at just the right position too.

A black motion system with two stepper motors. A green circuit board is fixed in a rotating cage in the center, and the entire assembly is on a white base atop a green cutting mat. Wires wind through the assembly.

Pi-lomar Puts An Observatory In Your Hands

November 20, 2023 by Navarre Bartz 5 Comments

Humans have loved looking up at the night sky for time immemorial, and that hasn’t stopped today. [MattHh] has taken this love to the next level with the Pi-lomar Miniature Observatory.

Built with a Raspberry Pi 4, a RPi Hi Quality camera, and a Pimoroni Tiny2040, this tiny observatory does a solid job of letting you observe the night sky from the comfort of your sofa (some assembly required). The current version of Pi-lomar uses a 16mm ‘telephoto’ lens and the built-in camera libraries from Raspbian Buster. This gives a field of view of approximately 21 degrees of the sky.

While small for an observatory, there are still 4 spools of 3D printing filament in the five different assemblies: the Foundation, the Platform, the Tower, the Gearboxes and the Dome. Two NEMA 17 motors are directed by the Tiny2040 to keep the motion smoother than if the RPi 4 was running them directly. The observatory isn’t waterproof, so if you make your own, don’t leave it out in the rain.

If you’re curious how we might combat the growing spectre of light pollution to better our nighttime observations, check out how blinking can help. And if you want to build a (much) larger telescope, how about using the Sun as a gravitational lens?

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A DIY Equatorial Mount Using Harmonic Drives

November 10, 2022 by Dave Rowntree 28 Comments

As an amateur astrophotographer will tell you, you just don’t get to capture the really interesting objects without spending a ton of money on some decent pieces of kit. Telescope aside, there really is a surprising amount of complexity, weight, and associated costs with the telescope mount alone, let alone one that is capable of any sort of programmable tracking. [Alan (Jialiang) Zhao] clearly wanted to up their game, and having suffered some of the shortcomings of their Sky-Watcher HEQ-5 pro Equatorial mount decided to go ahead and build an open-source mount, Alkaid, which hopefully works a bit better for them.

In simple terms, the difficulty of photographing an extremely dim, distant object (or one that is larger but diffuse) is that the camera sensor needs to spend a significant amount of time signal-averaging, to gather enough light for anything to be seen at all, through the noise. But, this ball of rock we sit on is rotating constantly, so the only solution is to track the object of interest, to compensate. This is referred to as equatorial tracking, and allows the rotation of the Earth to be compensated for during a long exposure.

The design of each of the two axes revolves (sorry!) around the use of a NEMA-17 stepper motor with a 27:1 planetary gearbox, driving into a harmonic reducer gearbox. Harmonic drives (aka strain wave drives) are pretty neat, working on the principle of a fixed, but circularly distorting ring gear that transmits torque from the inside surface to the outside, with almost no backlash. They are expensive parts, but for a super smooth movement, this is what you want. The huge output torque they allow, meant that [Alan] was able to build a mount for a heavy telescope without any counterbalances. Structurally, the whole thing is constructed from 10 mm thick aluminium plates that were cut with a waterjet and subsequently milled to finish. Continue reading “A DIY Equatorial Mount Using Harmonic Drives” →

Astrophotography On The Game Boy Camera

April 8, 2022 by Bryan Cockfield 4 Comments

The Game Boy Camera was the first digital camera that many of us ever interacted with. At the time it was fairly groundbreaking to take pictures without film, even though the resolution was extremely low by modern standards, and it could only shoot two-bit color. It’s been long enough since its release that it’s starting to become a popular classic with all kinds of hacks and modifications, like this one which adds modern SLR camera lenses which lets it take pictures of the Moon.

The limitations of the camera make for a fairly challenging build. Settings like exposure are automatic on the Game Boy Camera and can’t be changed, and the system only allows the user to change contrast and brightness. But the small sensor size means that astrophotography can be done with a lens that is also much smaller than a photographer would need with a modern DSLR. Once a mount was 3D printed to allow the lenses to be changed and a tripod mount was built, it was time to take some pictures of the moon.

Thanks to the interchangeability of the lenses with this build, the camera can also capture macro images as well. The build went into great detail on how to set all of this up, even going as far as giving tips for how to better 3D print interlocking threads, so it’s well worth a view. And, for other Game Boy Camera builds, take a look at this one which allows the platform to send its pictures over WiFi.

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Watching A Spacewalk In Real Time

March 31, 2022 by Al Williams 6 Comments

If you go to, say, a football game, you probably don’t get to see as much of the game as close as you do when you stay home and watch on TV. But there’s something about being there that counts. That’s probably how [Sebastian Voltmer] feels. While we’ve all seen video of astronauts and cosmonauts spacewalking, [Sebastian] managed to take a snapshot of a pair of spacewalkers from his telescope.

Of course, this wasn’t your ordinary department store Christmas gift telescope. The instrument was a Celestron 11 inch EdgeHD Schmidt-Cassegrain telescope on a very expensive GM2000 HPS mount. An ASI290 planetary camera took the shot. You can see the gear and more about the photos in the video below.

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Hackaday Links: January 16, 2022

January 16, 2022 by Dan Maloney 21 Comments

As winter well and truly grips the northern hemisphere, it’s time once again to dunk on Tesla for leaving some owners out in the cold — literally. It seems that some Model 3 and Model Y owners are finding their ride’s heat pump isn’t exactly up to the task of, you know, pumping heat. That this seems to be happening mostly in the northeastern US and southern Canada, where a polar vortex is once again dominating the weather and driving temperatures down into the -30 °C (-22 °F) range, perhaps speaks more to the laws of thermodynamics than it does to the engineering of the Tesla climate control system. After all, if there’s not much heat outside the car, it’s hard to pump it inside. But then again, these are expensive machines, some of which have had extensive repairs to address this exact same issue when it cropped up last year. It seems to us that owners have a legitimate gripe with Tesla about this, and they may be getting some help from the Feds, who are taking an interest in the situation from a safety standpoint. After all, no heat likely means fogged up windows, and that’s hardly conducive to a safe trip. But hey, that’s what self-driving is for, right?

Much has been made of the dearth of engineering cameras on the James Webb Space Telescope, and the fact that we’ve been relying on animations to illustrate the dozens of deployments needed to unfurl the observatory and make it ready for its mission. Putting aside the fact that adding extra cameras to the spacecraft makes little sense since the interesting stuff was all happening on the side where the sun doesn’t shine, we did get treated to what was billed as “humanity’s last look at Webb” thanks to an engineering camera on the Ariane 5 rocket. But not so fast — an astrophotographer named Ethan Gone managed to spot the JWST as it transited to L2 the day after launch. Granted, the blip of light isn’t as spectacular as the Ariane shots, and it took a heck of a lot of astrophotography gear to do it, but it’s still thrilling to watch Webb moving gracefully through Orion.

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