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

Bi-monthly release with minor bug fixes and improvements

Meridian flip still working for people?

I tried in simulation and it works. I will try today using my EQMod to see if there are any issues.
The following user(s) said Thank You: Vincent Groenewold
7 years 2 days ago #15670

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I had a failed meridian flip. It may have been set to >0 though.
7 years 2 days ago #15672

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I think it should also work at >0, but it may be the same issue. It's not that I missed a recent setting in the eqmod driver right?
7 years 2 days ago #15677

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Hi,
Concerning the log you gave above, all what I can say is:
  • you made a single point alignment, I suppose when you start your session, maybe 1h30 from the meridian, or near the pole, or else you check the Align Nearest mode
  • anyway, the delta_ra is 0.08, the meridian flip occurs at 0.06, so I think the goto, after alignment, does not perform a flip
I think that meridian flip should be initiated using true telescope coordinates, or alignment could be disabled when performing the flip.
In any case I would suggest you use more alignment points, the nearest model is quite simplistic.

Jean-Luc.
7 years 1 day ago #15682

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I just finished the live testing for merdian flip and it worked fine using the Nearest Point align mode. WIth N-Star there were a few issues, not with the flip itself, but with post-flip realignment process.

How would clients know about true telescope coordinates? From Ekos, I just monitor HA and issue GOTO to the same place once HA threshold is exceeded.
7 years 1 day ago #15683

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I'll check what my settings are, it could ofcourse be some comms issue, though I doubt that with the Ethernet connection. Or the mount itself has a problem. Thanks for checking!
7 years 1 day ago #15685

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indi-eqmod exposes true telescope coordinates in the align tab, and maybe every mount should expose them. Ekos monitors HA using aligned coordinates, and as said above, initiates the flip when HA is 0.06 above meridian. In the log the alignment process (be it Nearest or Nstar) reports a 0.08 difference in RA, thus the goto won't perform a flip. This is a feature, not a bug. Actually you may now use the Pier Side property as defined by Patrick (which uses true coordinates in the driver directly) to initiate the flip: there you will be sure the mount would perform a flip.
The other point was tthe number of sync points: using only one sync point is not very useful. And if you make your sync near the pole, a small error here is multipled by the inverse of the sinus of the declination. I wonder if this is not why some people get scope outside limts error sometimes.
The following user(s) said Thank You: Vincent Groenewold
7 years 1 day ago #15696

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Problem is that these features are only available in EQMod now. "True" telescope coordinates and Pier Side are only defined by EQMod (well, Pier side also defined LX200 Pulsar), but all other mounts do not define such properties nor it is possible to obtain them. I will see what else can be done on Ekos side.
7 years 1 day ago #15698

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Thanks everyone, very informative! I actually went into the habit of not syncing my mount at all before a session. This is because I noticed that the initial model it starts out with was already fairly ok and the platesolving takes care of the rest. But what you're saying is that for the flip, it is vital to have an accurate model, I'll try that.
7 years 1 day ago #15702

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Hi!

I'm not sure whether I am connecting to the topic or not - I have a Losmandy G-11, so no EQMOD here. But I have problems with meridian flip.

My situation: I've set the safety limit to 5 degrees past the meridian. According to the people who know more about this mount than me, issuing a Goto within 2.5 degrees of the safety limit should cause the mount to flip. According to my manual tests - using the handcontrol, not Ekos - this seems to be correct.

Now I tested this by tracking a star across the meridian, with 60 sec exposures. I've set the HA to 0.2, so as to make it happen within the zone of between 2.5 and 5 degrees past the meridian. It tracks, approaches the limits, and then, at 185 degrees, it seems to issue a meridian flip command - according to the capture model. However, I cannot see anything in the Indi panel for the mount. Issuing a manual Goto (with the Handcontrol, not Ekos) to the star it is already pointing to, initiates a Meridian flip.

It seems to me that no Goto command was issued - or what is happening here? Log files attached - Kstars log, mount log, and CCD log.

Magnus
Last edit: 7 years 21 hours ago by Magnus Larsson.
7 years 21 hours ago #15714
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I have tested Meridian Flip with the lx200_ap driver and AP1100GTO mount with the CP4 control panel and it works perfectly.
The following user(s) said Thank You: Jasem Mutlaq
7 years 20 hours ago #15717

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Hi,Looking at the log, it seems the goto command is performed as expected.
Now reading a document I've found here on pages 33 and 69, it seems the default goto limit is 122 degrees from east, and that you have to set it manually for goto commands perform a meridian flip. If I've understood there are some extensions to perform meridian flip in the gemini protocol, that the hand controller should use. For programs using only lx200 command set, you have to change this goto limit to 95 degrees if you want any goto commands perform a flip if target is 5 degrees past the meridian. I don't have such a mount so I can't help more, but you may start to look in that direction.

@Jasem
I wonder if you may not simply disable alignment during imaging in Ekos, so you would get the true coordinates. After all alignment is mainly used for goto accuracy.
7 years 20 hours ago #15718

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