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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Remote operation with no GPS lock (and CEM25P DST settings)

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Last night I went out to my club's dark sky site for my first try at imaging away from the comfort of home. Mount is a CEM25P, which has GPS built in. I have always used "Mount updates KStars" for time and location at home, but apparently the mount's GPS is not a fan of the remote location and could not obtain a GPS lock. I did not worry at first, because the HC does a pretty good job of keeping time without the GPS, and the location was only about 30 miles off.

Questions, before I lose everyone with the long version:

1) When I have set "Mount updates KStars", does KStar know there is no GPS info? (or does the mount refuse to send any data without GPS lock?) Is that why the perfectly reasonable time from the HC was ignored by KStars?
2) Does the CEM25P still need to have DST=No set in the hand controller? (along with manually changing the UTC offset to function correctly with the INDI driver?)

I think I have figured out how to deal with the problems I had with KStars last night, but I would be greatly appreciative if someone could read the long version of the story below and let me know if I'm missing something.

I got everything up and running, but the first time I checked what time KStars thought it was was when I went to select a star to do a guide calibration. It seemed odd that Jupiter and Saturn would be up at 10pm last night :)  KStars had some random mid-morning time. I found the screen to reset KStars time and set it to the correct local time. Told it to slew to Regulus, which it did correctly. Calibrated and focused, all so far so good. Slewed to M101, plate solved, all good.

Started guiding and the RA axis just zoomed off the chart and stayed there. Tried a few things (reboot, readjust RA tension bolt even though that has never been a problem before). Each time I restarted Ekos I did my usual routine of clearing Park and setting/saving Park to home position - but every time I parked it went to a spot a bit counter-clockwise from Home (looking from behind). This did raise a few thoughts about DST (and I have DST=Off in the mount handset), but out there in the dark field with no internet I was more focused on the guiding weirdness. Just about the last thing I noticed as I was resigned to packing up and heading home was that Ekos reported the mount as being on the east side pointing west, when I could clearly see it was on the west side (M101 was just about to cross the meridian), and the Mount tab said the meridian flip was coming up in just over 14 hours (kind of rang more DST bells, but 14 hours didn't seem to make any sense at all). Of course, it was the clarity of driving home that finally suggested that PHD2 was trying to move RA in one direction, but was actually pushing it farther away with each correction because the system did not know which side of the pier it was on. At least that is my current theory about why RA zoomed right off the graph every time I started guiding.

Tested at home this morning. Everything worked as it normally works at home when I was outside with a GPS lock. Came inside to prevent GPS getting a lock (and I realized that the pi gets time/date from the wifi network, so I disabled that interface and ran with just the astroberry hotspot, like out in the field). The pi and KStars booted up with some random time and date (Thursday, mid-morning). So I found the correct command to manually reset the pi date/time, which got KStars into the right place. Set time back to last night, slewed to M101 and it appeared to choose the correct pier side and reported a rational time to the next flip.

Is there anything I haven't thought of yet that would be a 'gotcha' the next time I go out to the dark site? Will anything weird happen if the mount decides to get a GPS lock in the middle of imaging, with 'KStars updates all devices' set?
2 years 9 months ago #71797

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I don't have an answer to this problem but I'm keeping an eye on this thread as I also have a CEM25p. Which I have only tested indoors, no GPS lock from the mount... and so far it's been behaving fine. Once I get all the last part for the Redcat, I will take the mount outdoor and do an imaging session, hopefully a GPS lock will happen and I'll be able to see if I get the same issue as you described.
2 years 9 months ago #71798

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Good luck! If you end up needing to tune the mount's guiding performance there are informative threads here (in Mounts) and on CN. Let me know if you ever need any of the iOptron adjustment pdfs.

In your testing, have you set KStars or the mount as the source for date and location?

The issue with DST is (was?) that the driver/mount combination does not correctly adjust to DST. The workaround is to set DST=No in the hand controller and manually change the UTC offset by 1 hour at DST / regular time changeovers.
2 years 9 months ago #71799

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I have 'Mount updates Kstars', I also have the pdf (I think) for the CEM25 tuning and yes it's about DST, there is a large post which mentions this www.indilib.org/forum/ekos/7753-meridian...-ioptron-cem25p.html
2 years 9 months ago #71801

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