This morning I discovered that in the middle of last night's session the meridian flip failed for (IMHO) no apparent reason.

Session overview:



Meridian flip is enabled, but has the pending status waiting:



Error message indicating that the flip has failed:



Error message indicating that the flip was successful, but not performed:



Does anyone have an idea what could have happened here?

Another night ...
And a succesfull flip ...

Really strange that there was suddenly 1 night where the flip goes wrong for no apparent reason.

Hi Fitchie,

I don't know exactly what happened there but I wouldn't use an HA of 0 as the trigger. The MF relies on the mount to actually move itself from 1 side of the pier to the other and the mount controls whether it thinks it needs to do a MF or not. If It doesn't think its past HA=0 then it won't flip (could just be a second or two, too early), which is what looks like happened. It then waits a while and retries. Not sure why that didn't work properly.

Anyway, setting a trigger = 0 puts you right on the cusp of it working / not working first time. If you put HA past the meridian, say equal to 10mins, then the mount should flip first time.

You can try this in daylight if you connect up your gear and pick a target about to cross the meridian and wait for it to flip. Its a good way to make sure you have it configured to work correctly and not crash into the mount / pier.

Thanks for your feedback.

Slowed down the flip to HA > 5 min and HA > 10 min and most of the time the flip succeeds, but sometimes it fails. Reason currently unknown. So I concentrated on the moments where things go wrong:





After some elimination I can conclude that the flip only goes wrong when a sequence is running and the flip is delayed until the last/current picture has been taken. Could it be that a double flip is being initiated: once through EKOS, once through the mount?

I have now set both in the mount that no flip should be initiated and in the EKOS settings that the mount should not receive a flip command.

Hi Ritchie,

FWIW, I have EKOS set to initiate a flip at 2 degrees past the meridian. I have the mount set to simply stop at 5 degrees past the meridian (I suppose I could set it to flip there). Since it takes 12 minutes for the mount to travel the 3 degree difference between the settings and I don't generally shoot exposures greater than 10 minutes, the meridian flips have worked consistently for me. When I have the settings changed (during a full reinstall of KStars where I lose my configurations) and I forget to set them right again, I can usually count on having to fix them.

Hope all your flips go well!

You are both right !

Values ​​equal to or slightly greater than 0 cause mysterious situations.

I'm now using 3 degrees or 12 minutes as the 'perfect setting' and in the meantime simulated 10 flawless flips during the day and performed 5 flawless flips during the last nights.

Due to the earlier shorter exposures in the past, I probably always stayed between ship & shore. But with longer exposures what I've been doing lately, things went wrong. Fixed now, thanks again.

Maybe other forum users can benefit from it too, so feel free...

Just for reference, a common reason the MF starts but nothing happens is that the time and/or location is not synronised between the mount and Ekos. Both have their view of things. This is a good setting to keep things synchronised...


I wrote this document a while back to explain how a MF works and how people might set it up on their equipment. Sounds like you may be past this stage now but you might some things in here helpful.


Let me know if you find anything wrong and I'll update it.

Fantastic document, have read it already quickly, but will definitely study it in detail later.
Thanks for that !

The only thing I still don't understand is why sometimes it takes 2 attempts to successfully perform a flip.

Here's a screenshot from last night:



1. MF initiated, waiting for execution (00:33)
2. MF not completed
3. MF re-initiated, waiting for execution (00:38)
4. MF successful completed


And this is the log:




Flip by mount command off:




Time settings:

A verbose log with mount and indi set may give a clue.

I am having a similar issue with my Losmandy Gemini G11 as of late:

The meridian flip triggers, but the telescope moves quite slow. I am getting tons of "Meridian flip completed" messages (like at lest a 100) in the log window, combined with thousands of "Mount unparked" (one every second) after that.
I can enable more logs for the next night and upload them here tomorow if that can help.

I have meridian flip set to flip if HA > 2.5°
Manual goto command works without issues.

As John has mentioned, it could be related to when a sequence is running during meridian flip trigger. It seems to trigger many many flips judging by the many "Meridian flip completed" entries in the log window.

EDIT:
In case it is relevant: I have a GPS device and have set GPS device to update Kstars.

I've never really had any flip problem in the past and it's only happened a few nights last month.
Also unable to reproduce it either, so I'm fine with it.


But your comment about a GPS does ring a bell...

I also (had) connected a GPS to the RIG and this is fixed on top of the telescope. When the telescope tracks higher objects, the GPS sometimes does not get a fix, because of the odd position relative to the satellites. And since my pier is always in the same place, my location does not change so I recently have turned off the GPS.

Probably it could be that in the sessions without GPS fix, as result of the time & location discrepancy between the mount and Kstars, the MF fails.

To the developers: is the GPS time only synced when starting EKOS or is this a running proces every x minutes?

That would actually make sense. I have the gps device also mounted on top of the telescope, however the antenna is just put on the ground and has a fixed position and does not rotate with the telescope.

I can test with GPS disabled and see if it improves the issues

EDIT:
I also set GPS to resync every 600s in the INDI control panel