Dear All,
Just to share about some problems I experienced when using StellarMate to hopefully help to avoid that other might invest as much time I had to (OS v1.6.1+ KStars v3.5.6 & INDI v1.9.3 Stable release).
The problem are the alignment errors reported by the Polar Alignment turned out to be wrong for my setup. It guided me but the results were apparently wrong and following guiding consequently a nightmare. Some days later I had a chance to examine what happened more closely.
Quick Read. Recommendatition is to deactivate the tickbox "Meridian Flip - Flip if HA>" in the mount tab while executing polar alignment for EQMod Mount. At least this seems to cause the problem for me and I could recreate it in tests.
More details:
After having trouble with polar alignment (wrong results) after updating from 3.5.5 to3.5.6 some days ago I downloaded the latest StellarMateOS_1.6.1.img.xz from the website to ensure I got a good base. I have been lazy though and re-imported my settings (from a 3.5.5 install)
I then ran the following tests:
3.5.2 stable
I started with this version to do a polar alignment with a version that worked fine in the past. I mechanically moved alt/az until I achieved a deviation of 0'22"
I made some test exposures and the guiding worked all fine. So the reported deviation of the ideal polar alignment is likely in a realistic corridor.
After this I did not touch the mount, i.e. the results oft the tests below vary only by the KStar versions and software settings
3.5.6 stable:
Polar Alignment made some crazy movements also with the freshly flashed card. The resulting error was calculated by the polar alignment to be 1°48'05'.
This is not realistic and a contradiction to the results reported for the exact same hardware setup by the 3.5.2 version just before. But I found in the status messages and the analyze file that the mount was initiating twice a meridian flip. The images I saw during the procedure were either showing star trails or appear to have been the same for all 3 positions. I could re-create this problem in several runs. I recorded an analyze file, if this is of interest.
3.5.6 stable - deactivated Meridian Flip
Next thing I tried was to deactive Meridian flip in the mount tab (unticked "Meridian Flip - Flip if HA>", I use the EQMod Mount driver for an EQ 6R). I then initiated the polar alignment again. Now the resulting error was calculated by the polar alignment to be 3'31'.
Much better but still not in line what the v. 3.5.2 reported. Maybe the algorithm had been changed in the meantime?
3.5.6 stable - reactivated Meridian Flip
Now I reactivated the Meridian flip in the mount tab again. I then initiated the polar alignment. The resulting error was calculated by the polar alignment to be 1°'47'48'.
With some more runs I could confirm the behaviour was dependent on the setting of the Meridian Flip (Tick box "Flip if HA>" ) in the mount tab.
I hope this helps others to avoid such problems even I have no real solution but feels more like a workaround. I will for now deactive the Meridian flip when doing polar alignment to be able to use version 3.5.6 with my setup.
It would be great if someone could share if the polar alignment code to determine the alignment error has ben changed from 3.5.2 to 3.5.6 which would explain the deviation of the results.
And maybe the development team might extract an idea what might be the root cause for this behaviour which was not in place for me up to 3.5.4 stable. In 3.5.5 I was affected by the FOV bug that blocked polar alignment completely so I cannot judge on 3.5.5
Thanks!
Kind regards,
Alex
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