Pointing at stars may seem easy on the surface—just mount a telescope to a tripod and you’re done, right? As anyone who’s spent time with a telescope can tell you, it’s not that simple, given that the Earth is always spinning. [Sven] set out to make his own mount to compensate for the rotation of the Earth, which led to some pretty amazing results.
In this project, [Sven] designed a GoTo mount, which is a telescope equatorial mount capable of being pointed at specific parts of the sky and tracking them to allow for long-exposure photos with minimal blur due to the Earth’s movement. He first went down the path of finding the correct harmonic gearbox for the steppers used. A harmonic drive system would allow smooth, precise movement without backlash, and the 100:1 stepdown would provide for the slightest of adjustments.
The steppers are controlled by a custom PCB [Sven] designed around an ESP32-S3. The first PCB had a mistake in the power delivery circuit. After a small tweak, V2 boards arrived and work great. The PCB runs OnStepX, a great open-source project centered around pointing telescopes, cutting down a lot of the software workload on this project.
After all the work put in, you may be wondering how well it works. [Sven] was able to get a pointing accuracy of 1-2 arcseconds from his mount. To get an idea of how great that is, 1 arcsecond is about the same as pointing at a penny from 4 km (2.5 miles) away. Fantastic results, [Sven], and thank you for sending in this great project—be sure to head over to his site and read all the details of this impressive build. If you found this interesting, be sure to check out some of our other telescope-related projects.
This is really great especially for disabled people, like me, so we can keep doing observations.
As an aside does anyone have the link for the startracker navigator project, I think it was a conceptual reverse-engineering of the star trackers used on US bombers, SR-71s and Polaris missiles for navigation.
https://wiki.openastrotech.com/
This one?
I don’t think that’s it, but I hope someone does come up with the link. Because that sounds exactly like a project I’ve had kicking around in my mind for a couple years now but haven’t had the time to start tackling . It would be pretty cool if someone else already did the hard work for me! LOL
Ok, I’ve had this thought when daydreaming about a sun tracking solar panel mount but maybe it could work for a telescope too.
My thought was, what if it was mounted on a frame with bearings so it could move easily and very weak springs that if no other outside forces are applied would bring it to a consistent center position.
Then add three of four arms extended out where their weight would pull the mount in each direction you need it to be able to move in. At the end of each arm attaches a liquid-tight container.
Hoses would run to the containers down to the base of the installation where pumps would move liquid in and out to move the mount.
My thought was that this way cheap fountain pumps or similar could be use instead of high-torque precision motors and gearing. Also, while this might be more prone to movement from a strong gust of wind it would just snap back into place afterwards whereas a motor and gear mechanism if forced to move might break.
Maybe I am describing something that already exists. I don’t know.
Pointing telescopes has been done since the invention of telescopes.
Once the magnification gets high (simplifying..) any movement or vibration wrecks what you are looking or may be more commonly what you’re photographing.
Maybe with newer digital systems (a lot of modern astrophotography systems just shoot high def video and restitch them in post) your idea could work but basically- movement =bad even if it self-centers.
For me: simple dob, nudge the scope when I need to. It’s a learned skill but has about zero ways to fail compared to digital and complex systems. Works for me!
I wish there was more info on the harmonic drives and where he got them. I can’t find the same thing on ali express.
https://nl.aliexpress.com/item/1005009016005267.html
To which currency does the penny belong to?