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Unrequested meridian flip through capture module?

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Happened to me to.... Don't think I turned it on as I didn't know it was there in the mount module.

Maybe the best approach in the mount module would be to default to whatever the mount's controller wants to do (default in Ekos: no action). Then call the option in the mount module a type of slew limit or override to the mount's own behavior.
4 years 10 months ago #38563

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Dear all experiencing an unexpected meridian flip: I will take a closer look into the log files and will come back to you.

Just one thing you could check in the meanwhile: Magnus (and maybe others as well): in your log file from 29.4. the MF happened while running a schedule job, not only a capture job. Is it possible that in your capture job MF is selected?

Since the scheduler reloads a capture job each time it executes it, it could happen that a previously disabled MF is enabled once again.

Please check or best please post your scheduler and capture jobs as well.

Wolfgang
4 years 10 months ago #38564

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Hi!

Yes, MF was enabled in the capture job enabled by the scheduler in last night's job. It was highly intentional. But it initiated an MF at a very strange time, long before the HA of 0.3 (I think) that I had set.

Magnus
4 years 10 months ago #38572

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Hi Magnus,
could you please check next time, whether the mount tab shows the right RA-values and the expected HA-value? And is it correct what is displayed for "Meridian flip in ... "?

Because the decision whether a meridian flip is necessary is taken from the current telescope position. Here is the relevant code snippet:
dms lst = KStarsData::Instance()->geo()->GSTtoLST(KStarsData::Instance()->clock()->utc().gst());
dms ha(lst - telescopeCoord.ra());
The meridian flip is executed as soon as a) no capture is running and b) the current HA > 0

As long as this incident is running, please disable the meridian flip in your capture sequence and set it directly in the mount tab - if you are willing to execute a meridian flip.

Wolfgang
4 years 10 months ago #38580

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Wouter, many thanks for your comment, it sounds very reasonable. The only explanation is "historical reason". It used to be only in the capture tab, but it turned out, that having it only there could create problems. For example aborted captures led to the situation that a meridian flip has been missed - which is problematic when some clouds fly by.

That's why I came across with the idea to shift it to the mount tab. The two ones are in sync, so if you change it in one place the other one is updated. But what really makes most sense, to be discussed. What about if we separate the discussion about an appropriate place from the problems described here?

Wolfgang
4 years 10 months ago #38582

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Thanks for the explanation Wolfgang. And I agree that this should be discussed in a separate thread. Could you please open one?


Wouter
Last edit: 4 years 10 months ago by Wouter van Reeven.
4 years 10 months ago #38583

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The following user(s) said Thank You: Wouter van Reeven
4 years 10 months ago #38585

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Hi!

Here is my sequence file that I used for that scheduler job last night.

I can not confirm the RA-values, since it was yesterday, but I can confirm that the telescope was imaging M51, the scheduler was targeting M51, and since it was M51 on the subs, it was pointing in the right direction. I can confirm that the value for MF (whether 0.3 or 0.4, I don't remember) as set both in the mount and the capture module, when the sequence was loaded (setting it in capture makes it be checked in mount too, and with the same value, at least for me....?)

I can confirm that despite the setting of MF to occur at HA 0.3, it did initiate a flip at about HA -01:24, read from the mount tab. SO: mount tab showed HA -01:24, and MF at HA 0.3.

I will not be doing much more of this for some time now, since my garden will be dug up and remade... and that is where I'm imaging from.. but I'll hang around here and try to be of help even so.

Best,

Magnus
4 years 10 months ago #38590
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Hm, that's strange. My first idea was that there is a timing misfit between mount and controlling computer. But when you see an HA of -01:24, it occurs 01:24 + 0:18 too early.

@others: please be so kind and post your logs and capture files as well. Maybe I can find a common pattern.
4 years 10 months ago #38597

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Hi Magnus,
there is one thing that I do not understand: does the mount really change the pier side although the meridian flip has been triggered more than 1,5h too early?

So there are two things that need to be explained:
  1. Why does the EKOS trigger a meridian flip although it is obviously too early?
  2. Why does the mount change the pier side although it is too early?

The only explanation for 2. that I currently have is, that the mount reports another RA position than EKOS. The decision, when EKOS triggers a meridian flip is based upon the RA position the mount reports.

Do you remember what RA position was shown on the RA tab? Did this value correspond to the RA position of M51?

And what was shown in the message for the meridian flip when the meridian flip happened? Did it really show -1:24? Or was it the value in the HA field of the mount tab?

Wolfgang
4 years 10 months ago #38699

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Hi!
No, the mount did not flip. No movement at the mount at all. If I got it right, Ekos issues a goto to present coordinates. THe mount is already there, so no movement, none at all, as I recall. If the mount were past the meridian and past the "Goto limit" on the mount, it would have flipped (or tried). So the mount must have thought it was too early for flip, so to speak.

No I don't remember the RA position on the RA tab. But Ekos had slewed to and aligned on M51, and it is really M51 on the subs, so in some sense coordinates were right. And the "icon" on the map, showing the position og the telescope, was right on M51.

And sorry, I don't remember the message during the "flip" more than it started post-flip align. But aren't those messages in the log file?

Hope this helps....

Magnus
Last edit: 4 years 10 months ago by Magnus Larsson.
4 years 10 months ago #38703

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Hi Magnus,
many thanks, that gives more clarity. So we can assume that the pointing position is in sync between mount and EKOS.

And no, the log does not report much. There will be coming a version with improved logging.
4 years 10 months ago #38704

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