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Meridian flip not happening

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Meridian flip not happening was created by Vin

Hello, so a weird thing has been happening the last few times I have used EKOS (its been v cloudy for a long time!). I have meridian flip ticked to happen once HA >0.10 hrs. It correctly calculates the time remaining for the flip for a target, comes up to it, says it flipping, and then says flip completed...but no flip has actually happened. I've tested it a few times & each time the same problem.

Here's a log file I saved from earlier tonight (look towards the end, for a test flip that didn't happen).

I'm not sure if its connected but when I park the mount (pointing roughly at Polaris) the RA is showing as 15h? Am I being silly? (Screengrab also attached). I don't they should be connected b/c the flip goes off the HA which correctly shows the minutes left before the object passes the meridian.
3 years 1 month ago #67900
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Replied by Vin on topic Meridian flip not happening

Sorry I hit send too quickly - just wanted to say thank you for looking at this!
3 years 1 month ago #67901

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Replied by Joaquin on topic Meridian flip not happening

At the celestial pole there is not RA, or in other words, you can get any RA value when roughly pointing to the pole.
Maybe this is related with your comment when you have your mount parked at the home position.
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Last edit: 3 years 1 month ago by Joaquin.
3 years 1 month ago #67911

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Replied by Wouter van Reeven on topic Meridian flip not happening

What mount do you use? In order for the meridian flip to be successful from Ekos, you need to make sure that the mount meridian flip setting is higher than the one in Ekos. In other words, if you set the meridian flip to happen in Ekos 0.10 hours (= 6 degrees) after the meridian passage, then in the mount this needs to be set to more than 6 degrees. My SkyWatcher mounts do not have such setting and Ekos typically retries the meridian flip several times before it actually succeeds and I have set Ekos to try the meridian flip after 3 degrees after the meridian passage. Eventually the meridian flip works for me.
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Last edit: 3 years 1 month ago by Wouter van Reeven.
3 years 1 month ago #67918

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Replied by Vin on topic Meridian flip not happening

Hi @wreeven, I use an HEQ5Pro. Where would this setting be for the mount? (The only place I know is the mount tab on EKOS - sorry if I'm missing something obvious!). It has flipped before in the past (at a setting of 0.1). Should I try setting it to 0.05 after HA if that works for you? I also found this thread (indilib.org/forum/wish-list/5505-modify-...n-flip-ha-value.html) where the OP seems to have got it to work w a bigger setting of 0.2. If the problem is the EKOS flip command is being sent too early compared to when the mount is configured for, maybe increasing EKOS flip to 0.15 or 0.2 HA would be better? (Although I wish I could see where the mount setting is!).

And thanks @jabian, yes you're quite right, that makes sense (I'm clearly an idiot!).

Cheers both
3 years 1 month ago #67919

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Replied by Wouter van Reeven on topic Meridian flip not happening

Hi @vineyard, my two mounts are HEQ5-Pro and EQ6-R. Like I wrote, there is no setting in the mount itself, apart from temporarily overriding the default value for the next GOTO. So your mount behaves like mine and all you need to do is to wait. When the first flip fails, Ekos will try again after several minutes (sorry, I am typing this off my head and I forgot how many exactly). Eventually the flip will succeed.

EDIT: Indeed this behavior will only manifest itself when the mount has been instructed to go to a target and when it it not parked.
Last edit: 3 years 1 month ago by Wouter van Reeven.
3 years 1 month ago #67925

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Replied by Jean-Luc on topic Meridian flip not happening

Hi,
Regarding the log, your mount is misaligned twenty minutes in RA. This is why the meridian flip does not occur: for the mount driver, the goto issued to perform the flip is still on the same side of the (mechanical) mount meridian.
[2021-02-28T22:48:16.902 GMT INFO ][     org.kde.kstars.ekos.mount] - Meridian flip: slewing to RA= "09h 17m 44s" DEC= " 53° 56' 07\""
[2021-02-28T22:48:16.902 GMT DEBG ][     org.kde.kstars.ekos.mount] - Setting meridian flip status to  4
[2021-02-28T22:48:16.903 GMT DEBG ][     org.kde.kstars.ekos.mount] - Slewing to RA= "09h 17m 44s" DEC= " 53° 56' 07\""
[2021-02-28T22:48:16.907 GMT DEBG ][           org.kde.kstars.indi] - ISD:Telescope sending coords RA: "09h 17m 44s" ( 9.29564 ) DE: " 53° 56' 07\"" ( 53.9353 )
[2021-02-28T22:48:16.978 GMT INFO ][           org.kde.kstars.indi] - EQMod Mount :  "[INFO] Starting Goto RA=9.29564 DE=53.9353 (current RA=9.6734 DE=52.432) "
Here the driver uses the alignment info to compute the telescope goto, the delta RA is 0.377650 hour, ~ 20 minutes.
[2021-02-28T22:48:17.002 GMT INFO ][           org.kde.kstars.indi] - EQMod Mount :  "[INFO] GOTO ALign Nearest: delta RA = 0.377650, delta DEC  = -1.503304 "
[2021-02-28T22:48:17.005 GMT INFO ][           org.kde.kstars.indi] - EQMod Mount :  "[INFO] Aligned Eqmod Goto RA=9.67329 DE=52.432 (target RA=9.29564 DE=53.9353) "
[2021-02-28T22:48:17.008 GMT INFO ][           org.kde.kstars.indi] - EQMod Mount :  "[INFO] Setting Eqmod Goto RA=9.67329 DE=52.432 (target RA=9.29564 DE=53.9353) "
This gives only 102 microsteps as the mount is still mechanically before the meridian.
[2021-02-28T22:48:17.086 GMT INFO ][           org.kde.kstars.indi] - EQMod Mount :  "[INFO] Slewing mount: RA increment = 102, DE increment = 0 "

Clients should use the true telescope coordinate to initiate a meridian flip, I believed that the PierSide property was reflecting this (i.e. was using true telescope coordinates to compute the property, not celestial coordinates).
But this may have changed.
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3 years 1 month ago #67982

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Replied by Vin on topic Meridian flip not happening

Thanks @geehalel. Do you know how I can correct the mount misalignment (does it need to purge the parking or something like that?)? I polar align (using the EKOS tool) at the start of every session, so should that not align the mount driver correctly too?

I've just done some dummy runs tonight, at 0.10 & 0.20 after HA, and the timer correctly shows when the flip should happen, the designated time passes, the status just changes to "Meridian flip planned..." & nothing more happens for a good few minutes after that (I stopped waiting after that). <This is a difference from the other night when it said the flip had actually happened>

The problem is that at 20 minutes of misalignment, the flip will happen too late & my main imaging scope will hit the pier and be useless for anything near the zenith. (I didn't use to have this problem so I'm also a bit confused on how the mount could misalign like this).

Thank you for any more help you can suggest!
3 years 1 month ago #68027

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Replied by Vin on topic Meridian flip not happening

PS the only PierSide property I can see in INDI Control Panel just says "West (pointing east)"? Thank you!
3 years 1 month ago #68028

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Replied by Vin on topic Meridian flip not happening

Hello, I just tried some more - just left it running on a dummy run indoors while watching the news. It got to +47mins and still no meridian flip. There seems to be something seriously wrong? The LST on the Mount tab is correct. Thank you.
3 years 1 month ago #68039

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Replied by Jean-Luc on topic Meridian flip not happening

The alignment info comes from the syncs you made with astrometry (and to be accurate in RA this should **not** be done near the celestial pole, see @jabian comment).
This info is eventually saved into an alignment file (for fixed observatory) and reused between sessions. Your log file starts after the mount driver inititalization, thus I don't know if this is your case.
Look into your <code>.indi</code> directory for a <code>AlignData.xml</code> file (this is the default name), and rename or remove that file.
When you restart your session (and before any sync), the delta RA should now be zero.

I wonder if loading this AlignData file is actually used by fixed observatory users, I believe they make the best polar alignment they can do once, and sync their mounts on every sessions without saving these AlignData.
Maybe this feature could be simply suppressed/disabled, as it seems to create confusion rather than being really useful.
3 years 1 month ago #68044

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Replied by alacant on topic Meridian flip not happening


Hi
Go back to basics?

Turn off the mount and physically set RA and DEC level. Use a bubble level. Horizontal for RA, CW level. Whilst you're there, zero the DEC setting circle then make sure that the park command -from anywhere- also zeros the circle. Finish every session by parking the mount.

Connect the mount, Clear the mount model for good measure then polar align.

Next, in align, capture and slew to target, anywhere away from the home position. Dubhe is good.

Set the mount to flip at least 0.2 hours after the meridian.

That's it.
HTH.


Cheers and HTH.
Last edit: 3 years 1 month ago by alacant.
3 years 1 month ago #68070

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