I needed a way to focus while looking at the camera, but all the motorized focusers I could find were way out of my budget, so I decided to design my own. ?It uses an Arduino to control everything, running software I wrote. ?A stepper motor drives the focus knob, and I have a hand controller with a rotary knob and display. ?The Arduino is in its own box attached to the pier, so that motion of the telescope doesn’t drag the hand controller around. ?I designed the plastic parts and had them 3D printed, the rest of the parts came from Adafruit.

If anyone is interested, I’d be happy to share the design.

Now the question is, how to determine when the focus is optimal. ?I can drive the Nikon using gphoto on a raspberry pi (I’d rather not take a laptop out to the telescope but if I have to, I will use a MacBook). ?With that software I can capture jpg or nef files onto the raspberry pi. ?Can anyone suggest software that can read a jpg and either do fwhm or some other measure of sharpness? ?I’d really like it to report sharpness of the whole photo as a single number.

Rick