Re: 400GTO


Roland Christen
 

A loose nut will show as backlash in PHD. Will see it if you physically push and pull on the axis
A worm that's not fully in mesh will show as backlash in PHD. Will see it if you push and pull on the axis.
A spur transfer gear that's not fully in mesh will show as backlash in PHD. Will not see it by pushing and pulling on the axis.

3 places to look. Take covers off and explore.
If you can't figure out where the backlash is coming from, you may need the mount serviced. I'm sure we can find the place that has backlash.

I don't know your particular build, but I believe this mount has a stepper drive with a gearbox on the stepper. If none of the above, then it's possible that the gearbox has inherent backlash. In that case we may or may not be able to fully fix it. It is a very old mount that goes back some 30 years, and may have seen a lot of use (and wear). Backlash inn the stepper gearbox will not be visible as play in the mount axis (when you push and pull on the back of the scope).

Roland

-----Original Message-----
From: Chris White <chris.white@...>
To: main@ap-gto.groups.io
Sent: Mon, Jul 4, 2022 4:46 pm
Subject: Re: [ap-gto] 400GTO

Good tip on the nut. 

Would A loose nut be seen as backlash in phd?

You are correct. While I feel wiggle in both axis, I only have a problem in declination. The backlash is so great that it is not able to be measured by guiding assistant. 

--
Roland Christen
Astro-Physics

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