[ChrisV (Chris)]

Finally put together the onstep controller. Well nearly finished - just have to sort out fixing connectors near the steppers. I've built this on an EQ5 mount that I got here on IIS.

Built using the new miniPCB designed by Howard Dutton (used easyeda.com to get them made).

For the controller I've used TMC2130 stepper drivers which can do 32 microsteps during tracking. Used 200 step/rev NEMA14 steppers with 2.5:1 belt driven pulleys. With the 144:1 worm this gives 0.5arcsec/step during tracking (microstepping ON) and GOTOs of 4.9deg/sec (microstepping OFF). So reasonable accuracy with good GOTO speeds - the NEMA 14 stepper can just handle this (I might try some NEMA 17 steppers with 400 step/rev).

I have used bluetooth to control the mount (but will eventually put in the wifi adaptor). Star alignment done with the onstep android app, and then navigate with SkySafari.

Took it out on the weekend and did a quick Eta Carina = 58x 20sec subs (20min total, no guiding - captured with APT processed in PI). See attached pics of the full frame (x4 binned) and zoomed in (no binning) to show that the stars look reasonable with the pictured scope/camera which is 2arcsec/pix resolution.

Thanks for pointing me to the onstep build. This is going to be my portable mount for wide FOV imaging. Its pretty light - can carry the whole scope/camera/mount without too much of a struggle.

Chris

Edit: pics are
- 2x Eta Carina
- Inside the onstep controller box & stepper mounted on DEC axis
- Scope on the mount - black box is bluetooth onstep controller, white box is dew heater controller and 12V distribution & USB hub