Re: Tracking Accuracy


Khalid Baheyeldin
 

Hitosi,

Thank you for your suggestions.

On Wed, Sep 26, 2018 at 09:58 AM, hitosi sato wrote:
High frequency PE error offen caused by the eccentricity of the pulley for the belt or gears.
In my case, the pulleys cannot be a source of the high frequency observed in the photo that
shared with the group.

The reason is: the pulleys in my case are 1:1, so whatever errors are in the pulleys will be
in step with the worm gear rotation.

Additionaly It also caused by the precession of the worm screw.
If you mean the worm gear itself, then that is the lower frequency wave (one rotation every
480 seconds, and two rotations in the original photo.
There are many mechanical causes of PE errors.
If you can download this paper(Sorry this paper written in Japanaese, Famous mount maker's report about PE error)
http://www.u-han.co.jp/u-150/U-150.pdf
Please look at the pictures of this document. You can imagine about PE error.
Thanks. The diagrams are informative.

you should try to record the guide log and check the details in a PHD log viewer etc.
It may be the gearbox on top the NEMA11 motor (which is 18:1).

Howard mentioned Declination as well, but I don't completely understand that. Perhaps
I should try another time night with an option to power down the Dec axis and see ...

Join main@onstep.groups.io to automatically receive all group messages.