LC (Low Cost) Star Tracker

DEVLOG 003
I worked a lot on the equatorial wedge, researching it on YouTube and the internet, and I made a pretty solid base design. I think it will be a pretty stable mount. I have decided not to implement the fine adjustment screws. After seeing a YouTube video, I can simply use NINA star-guided polar alignment, since it is not supposed to be such a portable mount. I also decided that I will 3d print a curved slot holder in the back, that will screw onto the base eq wedge, and have a slot shaped to match the radius of the wedge’s circle, so I can support the backside evenly, when the telescope is mounted. I also organized the Onshape files, and started a notebook. Initially for the eq wedge, I wanted it to just be one single bar in the middle, as it would be simpler. I decided to provide adequate support for the back side of the RA Axis that is sticking out, I would need a curved profile section, like shown in the OG Star Tracker V2. This would provide good stability even for heavier payloads. Next session I will work much more on the details of the smaller parts, and also order the pulleys and rods and things, to begin making it and getting rough estimates in real life.

DEVLOG 002
Worked on the initial design for the declination axis for the star tracker.
My goal for this section of the tracker is to be much more compact and lightweight, since the RA axis will rotate it, and we want to minimize the load on the RA axis to allow more of its strength to be used by the telescope.
I made a very simple outer frame, with the posts in the center rather than a traditional simple box design, to make room for the large 80-tooth pulleys. I think this design is quite innovative, as it really compacts everything together, with the first two stages on one simple axis, and the third and final 80-tooth pulley is sitting on the other side of the frame, where the telescope itself will be attached to.
I also did the major task of deciding which bearing to use, and I settled on the simple, standard F695ZZ Flanged Ball Bearings. They have a 13mm OD, which would allow me to drill the proper-sized hole into the aluminum extrusion and press fit it, and then either use specialized Loctite glue or some kind of 3d printed fasteners to hold the bearings in place. This is also a very cost-effective solution as 20 bearings only cost $15 on Amazon with fast shipping, which will help stay in the $100 budget.
I also assembled the complete assembly with both axes attached together, to which I will attach the EQ wedge. I have also decided that this EQ wedge wil have built in screw adjustment system, so I can get super super accurate polar alignment using NINA’s or other software’s 3 point polar alignment. Im still not totally sure if I can add a polar laser or scope to take this tracker out away from home, because that would be very helpful for travel.
The next major thing to do for the next session will be to get the proper belt length estimates and properly lengthen the aluminum extrusions to get the correctly sized RA and DEC axes. I will also do lots of math calculations about possibly increasing to 8mm shafts, if possible, if the extra thickness will really help or not, and if the extra cost is worth it. I will also work on the whole EQ wedge and make the screw adjustment, with the proper mounting solution to my current tripod.

DEVLOG 001
Worked on initial CAD for the Right Ascension Axis.
I created a simple aluminum extrusion frame to get a super simple base design created. The aluminum extrusions are currently 10cm long, and I made a simple estimate for the length of the steel rods to be at 8cm for fitting the pulley spacings correctly.
One major achievement, was I found an incredibly good place to put the stepper motor. I placed it inbetween the four 80 tooth gear, perfectly inbetween without contacting any surface. This also allows me to slide it back and forth, to adjust tension for that specific belt loop. For the other loops, I will try to come up with a simple tensioning method, as well as bearings for the next work session.
Thank you.