Measuring focuser backlash for SCT primary mirror adjustment

[Graeme Holyoake]

Robert,

First of all I'd like to say thank you for all of your work in developing this project. I have recently completed building my version of your focuser using a ULN2003/28BYJ-48 combination, and it's all working nicely.

In order to get the best out of automated focusing I'd like to be able to set up the backlash parameters, but I'm struggling to see how I can do this for my SCT when I'm using the primary mirror focus adjustment. I'm sure this must be something that has been done before but I'm failing to understand how to go about it.

Is this something you can offer any advice on, or do I have to accept that it won't work very well and that I always need to make my final adjustment in the same direction?

Thanks and regards,
Graeme Holyoake

[brownrb]

I always need to make my final adjustment in the same direction - yes this should be the case

as recommended in the pdf, you wil experience issues trying to do this visually (due to multiple steps within the cfz). And it is gonna be very challenging trying to use some digital guage as well considering it is an SCT. It make be just a case of trial and error.

Maybe there is someone here who can answer, as I do not have any SCT scopes. Failing that perhaps post the question on a forum such as SGP (ask it as a generic issue rather than a myFocuserPro2 issue please) or APT or cloudy nights etc.

Regards
Robert