Over the past months i've designed this mount for my DSLR camera. Not satisfied with the performance of the various barn-door tracker models that are available, i decided to go for a completely different design; the not so common EQ split-ring. The huge diameters mostly compensate imprecisions from printing and the cheap steppers that i'm using.
After the initial prototype i saw the potential for two axis GoTo, so I added that. After an initial calibration over Polaris HA, you can put RA and DEC coordinates (JNow). It works pretty well but is not extremely precise, theres a deviation of a few arcmins over a quarter rotation (6h). But its enough to usually put the target into the FOV, even with my 500mm lens.
The tracking works very well. I've gotten consistent exposures at 60 and 120s at 330mm. Even at 800mm (500mm and APS-C camera) it tracks for 30s to 1 minute, but not as consistent. Here helps the Autoguiding capabilities. Yes, i've written an ASCOM driver and designed a guidescope. Its on the top in the picture. The guidescope uses a cheap 50/182mm achromatic doublet and a standalone AR0130 b/w sensor. The body is printed of course. With that i've easily achieved 5 and 10 minute exposures at 330mm and up to 5 minutes at 800, although thats completely overkill for where i live.
My biggest lens plus camera weights around 2kg and the mount takes that without problems. I cant test it myself really, but i'd say the maximum payload is around 3kg. The maximum length of a lens is somewhere between 20 and 30cm depending on its weight, as it has to be balanced properly. I have successfully used a 45cm long lens, but the GoTo wont work anymore.
The polar alignment is done semi-automatically using the steppers and the DSLR screen. The adjustment is done over the large screws on the front and back.
A lot of functions could be added to this, but i'm limited by my coding skills. Theres already people talking about writing the code for various functions like star align, full-auto PA, bluetooth and PC control.
I have some pictures taken with this on my IG, but only the last one is with guiding and the newest upgrades (mainly the belt drive thats much better), so the others arent perfect.
The files are available here: https://www.thingive...m/thing:4167783
Source and CAD files are available here: https://github.com/O...penAstroTracker
Oh, and I opted for the cheapest possible components to make this, so building one costs around 50 bucks (Not including the guider)