4,5'' (114 mm) dobsonian telescope (electrical Alt-Azimuth mount)

thingiverse

This is a design for a Dobsonian reflector telescope, with a primary mirror diameter of 114mm (4,5'') and a focal point at 900mm. The primary mirror and secondary mirror were obtained for free, while all other materials are low-budget or 3D printed. To achieve basic tracking while observing an object, I designed an Alt-azimuthal mount that can be controlled using a joystick and a system of NEMA17 stepper motors. WARNING: This is still a work-in-progress project. A moving box is being designed to house the telescope, with electronics also planned for placement inside this enclosure. I uploaded the electronics layout for movement control earlier, though it has yet to be tested. The main components include: - Power supply: 12V/5A - 3 NEMA17 stepper motors (42mm height without shaft) - Arduino Uno - Arduino Joystick - 2 Polulu stepper drivers - 2 100V/10uF capacitors (between power supply and Polulu's) - 2 10K resistors - 2 100K resistors (between 5V line from Uno to Polulu's) - 6 jumpers (for microstepping of Polulu's) A layout for soldering all components together will be provided once the system has been tested. More updates on this project are forthcoming. On January 26th, I uploaded a soldering program for the driver board, using through-hole soldering due to its simplicity. The connection between the driver board and Arduino Uno is made with jumper wires (male-male). On February 9th, I removed one part (mount finderscope) that didn't work as expected, replaced another part (secondary mirror tube) for added sturdiness, and included a reinforcement triangle for the mirrorbox. The new mount for the finderscope is still in progress. A bill of materials (BOM) is being compiled; I just need to add parts used in the finderscope mount, which is currently unfinished. On February 19th, all necessary parts were re-uploaded as .stl files along with some renders and a BOM for completed parts. If any issues are found, please let me know. Electronics-wise, I'm still awaiting delivery of an Arduino 2-axis joystick, preventing complete assembly testing. On March 9th, the joystick finally arrived, enabling initial testing. The system functions as intended. For users' benefit, I uploaded Arduino code and necessary libraries (''bounce2'' and ''Accelstepper'') for compilation. An additional README file provides explanations. Further updates are expected over the coming days. On May 11th, after several weeks of inactivity, progress was made on designing and testing a more solid movement system. A short film of the moving telescope is available. The base assembly and mirrorbox assembly have undergone changes. I updated the BOM-list. With these modifications, the telescope's movement will be smoother, with an increased area of 22°-70° (to the horizon) accessible for observation. The finderscope remains challenging to implement; further progress is anticipated in upcoming weeks. If any builder has made design changes, feel free to upload them to help create a desired prototype. On May 28th, additional photos were added, showcasing the build process. A small gear was updated, eliminating the need for M3 tread cutting on previous versions.