An Accurate Measurement Method for Telescope Focusing System Backlash

[Frank Chen]

I am very glad to share an artical with you:An Accurate Measurement Method for Telescope Focusing System Backlash

The measurement method of the telescope focusing system backlash described in this article was discovered suddenly when I was checking two autofocus curves with a friend some time ago. At that time, a friend sent me two pictures of autofocus curves. The curves are very smooth and fitting well, but the focus position differs by about 400 steps. Normally there shouldn't be such a big difference. Then my friend told me that the backlash compensation direction of the two focusing is different. One is IN and the other is OUT. Then I realized that this difference is actually the overall backlash of the telescope focusing system including the telescope focuser and the electronic focuser. A few days later, I have a clear sky and I repeated the measurement method. This article is an introduction to this method. Hope this method will be useful for astrophotographers.

Here is the link of the Artical:https://theskysearchers.com/app.php/art ... m-backlash

[Graeme1858]

Thanks for posting your Article Frank.

It is an interesting method for finding an accurate value for focus backlash. I'll give it a try next time I'm out.

Regards

Graeme