Motorized Focuser for RedCat 51

thingiverse

This is the motorized focuser for my RedCat 51 telescope. I've already published my manual precision focuser (https://www.thingiverse.com/thing:3913819). This project builds on the same DNA as that one but with a stepper motor drive. The design utilizes two rings from the previous focuser, one ring is modified to anchor a motor securely to the body of the telescope. The motor drives a belt which is attached to the other ring. The belt is secured to that ring by a belt clamp designed by David Bunch (https://www.thingiverse.com/thing:925911). To give the belt more tension, I created simple shims in three sizes (1.5, 2.0 and 2.5mm) available here on this page. Here are the parts I purchased - not including the telescope: 1. The Arduino NANO (https://www.amazon.com/gp/product/B0713XK923). 2. The motor and driver board (https://www.amazon.com/gp/product/B01J507JGS). This is a 12v motor and matching driver, 5v isn't enough. 3. The timing belt and pulley (https://www.amazon.com/s?k=GT2+Timing+Belt+for+3D+Printer&ref=nb_sb_noss). 4. A 12v power supply (https://www.amazon.com/gp/product/B077PW5JC3) for the motor, the 5v for the NANO is supplied by the USB connection. I made a YouTube video showing the assembly and belt adjustment. (https://youtu.be/dg9NPVzu5ts). As soon as I get a clear night, I'll try some actual focus on stars and I'll post the result on YouTube. (2/27/2020 - done. It's up: https://youtu.be/ytMzCFp5L_c). (5/28/2020) - it doesn't play well with autofocus. Several factors are at work here, not least of which is seeing. I don't use autofocus but I do focus remotely via APT using its HFD measurement. The focuser works very well under my control when I count only the minimum HFD at any given position. I operate the focuser from an Arduino NANO running open source software written by Dave Wells. I refer you to SourceForge (https://sourceforge.net/projects/arduinoascomfocuser/files/Mark2/) where you can download his software and his matching ASCOM driver. It's been almost 4 years since his last update, but there is still activity on the project. It's basic, easily understood and it works.