Hi @PMTeam@ZWO ,
I would like to report an unexpected guiding event that occurred during an Autorun session and ask whether this could be an ASIAIR/AM3 issue.
Setup
ZWO AM3 mount
ZWO ASI2600MC Air
Integrated ASI220MM Air guide sensor
TS-Optics CF-APO 90, 540 mm focal length
Guide exposure: 1.5 s
Guide pixel scale reported by PHD2: 1.53 arcsec/pixel
RA: Hysteresis, aggression 65%, MinMo 0.10
DEC: Resist Switch, aggression 65%, MinMo 0.10
Max guide pulse: RA 350 ms / DEC 400 ms
Dither: both axes, scale 1.0
Guiding during the session was normally very good, around the sub-arcsecond level.
The problem occurred during Autorun frame #57, a 300-second exposure.
The exposure started at approximately 02:40:26 local time.
At approximately 02:43:39, while the exposure was still running, the PHD2 log shows a sudden guide-star displacement of about 28.4 pixels, corresponding to approximately 43.5 arcseconds at the reported guide scale.
The excursion was mainly in DEC. PHD2 then issued repeated maximum-length DEC corrections (400 ms) and eventually recovered.
What I find unusual is:
there was no dither at the time of the excursion;
the previous dither had completed more than 3 minutes earlier;
the next dither occurred only after the 300 s exposure had finished;
the guide star does not appear to have been lost: star SNR remained around 44–47 and the PHD2 ErrorCode remained 0;
I did not touch the mount or telescope during the exposure.
When I noticed the problem in the ASIAIR app, the displayed total guiding error was still around 15 arcseconds. Reviewing the PHD2 log afterwards showed that the peak excursion had actually reached about 43.5 arcseconds before recovering.
The affected 300 s light frame had clearly trailed stars and had to be discarded. All the other frames from the session were usable.
Could you please check the attached ASIAIR Autorun and PHD2 logs and help determine what caused this sudden movement?
In particular, I would like to understand whether this could have been:
an unexpected guide/mount command;
an AM3 control issue;
an ASIAIR guiding issue;
or something else visible in the logs.
I noticed that other users have reported degraded guiding and unexpected guiding excursions after recent ASIAIR/firmware updates, including reports in the ASIAIR v3.0 release thread. I am therefore attaching the complete PHD2 and Autorun logs to help determine whether my event is related.
Thank you.
