Raspberry Pi Star Guider with Offset Adjustment Platform

thingiverse

Offset adjustment platform for Raspberry Pi auto guiding system. Overview -------- This is an integrated solution where the RPi board and the guide scope are being mounted onto the telescope. The goal is to allow fine offset adjustment of the guide scope, and to allow wireless, computer-less auto guiding. ### Offset Adjustment The platform includes a azimuth adjustment mechanism through a worm gear - spur gear set, and a altitude adjustment (tilt adjustment) through a curved sliding rail. This solution is more explicit and easy to control compare with the 2-pivot guide scope holder system. ### Auto Guide This system utilizes Raspberry Pi 3 and Raspberry Pi Camera (support both v1.3 and v2.1) as the auto guiding infrastructure. You can install your favorite OS (Ubuntu Mate, Raspbian, etc.), your favorite guiding software (OpenPHD, lin_guider, etc.) and any guide scope with a C/CS mount upon your focal length needs. My own solution tested on Ubuntu Mate with OpenPHD 2.6 installed. Using INDI to control my Takahashi EM-11 via bluetooth-serial adapter (or SkyFi) and remote control the RPi using the WLAN built-in on the RPi 3 board, I can implement a complete wireless guiding solution. (A battery hang on the case can be used as the power supply!) Depends on what guiding software and guide scope you are using, the result may be vary. In my experience, using a f=75mm f/2.8 CCTV lens with OpenPHD is not possible to spot any star on the night sky. This could be due to lack of exposure control of RPi-V4L2. Either switching to other guiding software (python based) or using a better scope can perform better. Though both the v1.3 or v2.1 RPi camera should have high enough resolution in cooperate with f=100-200mm guide scope. I can get some good result using a f=100mm f/2 scope to guide my Tak. FSQ-85. Instruction ------------ This stuff includes six 3D print parts, one RPi 3 board and RPi camera, a metal C/CS mount, many little screws and a set of gear. You can also find a printed version of C mount here https://www.thingiverse.com/thing:2728134. ### Bill of material 3D Printed parts ----------------- 1. RPi Camera holder 2. RPi Box Base 3. Slider 4. Azimuth Rotator 5. Spur gear (optional) 6. Worm gear (optional) Tools ------- * Screw drivers for small screws * 3.2mm drill (to bore holes for M3 screw) * [optional] M3 tap * [optional] M4 tap * [optional] 1/4" tap ### Assembling Instruction to assemble the system is quite straight forward. Please refer to my photos for hints. 1. Fix the C/CS mount onto the RPi Camera holder using 4 1.7mm screw 2. Fix the RPi Camera onto the RPi Camera holder using 4 1.7mm screw 3. Fix the RPi Box Base onto the Slider using 4 1.7mm screw 4. Fix the RPi Camera assembly onto the RPi Box Base using 4 M3x15 screw and nut 5. Fix the RPi 3 board onto the RPi Box Base using 4 2mm screw 6. Cover the RPi Box Cover to the Base using 4 1.7mm screw 7. Load the slider with M4 handle screw and M3 locking screw 8. Insert 2 nuts on the bottom of the Azimuth Rotator 9. Load 2 M3 locking screw on the bottom of the Azimuth Rotator 10. Fix the spur gear onto the Azimuth Base using 1.4mm screw (you may need to drill some holes on the spur gear) 11. Drop the worm gear into the slot on the bottom of the Azimuth Rotator 12. Puncture the 2mm metal rod through the worm gear and the Azimuth Rotator 13. Tap the center hole of the Azimuth Base with your favorite size (1/4" will suit most case) 14. Place the Azimuth Base into the Rotator 15. Finish