Here are some comments based on what's in the
log:
1. Don't try to calibrate at or near the pole.
Calibrate close to Dec=0. When you get a good calibration, keep using it,
don't keep doing it over and over, just calibrate at the start of each
night.
2. Don't use LowPass2 for your Dec algorithm. Your
setup has numerous mechanical problems and isn't nearly stable enough to use
that algorithm. You should revert all the guiding parameters to their
default values - your problems are with the gear, not PHD2.
3. Your mount has a lot of reversal delay (backlash) and
probably too much resistance (stiction) in Dec. If you increase the mount
guide speed to 1x sidereal (or close to it), the situation will improve somewhat
but you will probably need to also make mechanical
adjustments.
4. There are sometimes large, abrupt guide star
excursions that push the Dec axis into instability. These are not caused
by guiding, they are probably caused by something moving around in your guiding
assembly.
Dec is in green here. At the point this large excursion
started (arrow), the Dec motor wasn't running at all. If you reposition
your scope to point at Dec=60:00:00 and RA=03:00:00, do a careful inspection of
the whole guiding assembly - scope, mounting points, cables - to see if anything
can pull or move around. It only has to move by about 15 microns, about 1/3 of
the thickness of a human hair. That's a consequence of the tiny pixels in
your guide camera and the finder-scope you're using for guiding. Also make
sure that the scope is well-balanced in Dec with the clutches
tight.
Good luck,
Bruce
From: 'rwhite' via Open PHD Guiding
[mailto:open-phd...@googlegroups.com]
Sent: Tuesday, January 11,
2022 8:21 AM
To: Open PHD Guiding
Subject:
[open-phd-guiding] 2 months ago PHD stopped accurately
guiding