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Meridian flip interrupted on EQMOD mount - Alignment Module?

I tested today in my observatory without alignment/focus/guide checked and it worked as expected. I set the HA > 0.2
4 years 3 months ago #46653

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I started working through things last night but it clouded over while I was doing tests.

I can say definitively that it is NOT the Scheduler, at all. I can create a no-flip scenario without the Scheduler.
I can also say definitively that it is NOT the HA offset - I was able to get a no-flip with an HA > 0.2.

My tentative conclusion is that it is weird. Like very weird.

There does seem to be a relationship between using plate solving on the guider device and interrupted meridian flips. Ironically, the clouding over further pointed the way towards such a relationship, one that I suspected from the start (it's in the thread name, after all).

Before it clouded over, for all of my tests with a guide camera attached I was also doing plate solving with the guide camera and ending up with no-flips. But once it clouded over, I couldn't plate solve any more so I didn't (just pointed it at objects approaching the meridian and let it do its thing), and all tests after it clouded over came through with successful flips - which is consistent with my daytime dummy runs where I also never had a failed flip.

Tonight is looking promising for clear skies, and with the possible problems narrowed down I should be able to come up with a definitive scenario for these failures.

So I'm looking at the following setups in my INDI device profile for my equipment, an EQ6 mount and a ZWO ASI120MM camera:
Mount: EQMOD
CCD: None or Simulated or ZWO
Guider: None or Simulated or ZWO

The key pair of tests will be with the ZWO camera as guider and then (1) plate solving and (2) not plate solving prior to a meridian flip. I'm expecting to get no-flips following a plate solve with the guide camera, and flips without having plate solved with the guide camera. I'll also test plate solving with the ZWO as the CCD to see if the issue is generalized to the ZWO or limited to when set to the Guider device alone. Given I suspect a role for plate solving, I'll be including that in the logging.
4 years 3 months ago #46662

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I've got a couple of ideas what could be happening. It needs verbose logging the mount driver to see exactly what commands are being sent to the mount and logging of the guider and align modules to see what they are getting up to.

If I'm right it's unlikely to happen with simulators because it needs real data. It also explains why tests when it's cloudy don't fail.
4 years 3 months ago #46665

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Well the results are interesting and kind of discouraging.

The main takeaway is that plate solving even once impedes the ability to properly meridian flip, so it's not even target-dependent. So, for example, if the mount is aimed at M33, plate solved on that and then moved to M31 which is approaching the meridian without actually plate solving on M31, the meridian flip will still be interrupted, so it's not like a plate solve on M33 only impedes the subsequent flip while tracking M33. So long as I don't plate solve, it flips as many times as I have patience to line up flips for, but once plate solving is carried out once, meridian flips are interrupted and INDI has to be restarted to reenable them. Parking and unparking is not sufficient to eliminate the interruptions and neither is disconnecting and reconnecting Ekos.

It doesn't matter whether the ZWO is attached as a CCD or as a Guider in the profile - the controlling variable is plate solving. And with respect to plate solving, it matters not whether it's set to Sync or Slew to target after solving - the effect is the same.

When I tested the effect of guiding, it opened up a whole new can of worms. Naturally I had to test it without plate solving first. Guiding didn't seem to impede a meridian flip from proceeding, but the one that was initiated during autoguiding never actually "completed". It was perpetually "Running" even when it had actually finished. That didn't stop the mount from being able to be parked, where it still maintained a status of "Running".


I have logs for this and since I recorded times of meridian flip [non-]events I'll go through and pull out a few segments where they were invoked. "Verbose" is an understatement to these logs...
4 years 3 months ago #46674

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Well folks, I tried again with having the guide simulator to do the solving and the flip happened... maybe something is off with using the real equipment. At any rate, I need to reproduce it exactly in order to figure out what's going on.

@Chris Please share any findings you have, I'd like to get this sorted out before KStars 3.3.9 is released.
4 years 3 months ago #46680

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My theory is that a command is being sent to the mount which halts the slew. A log file showing the mount communication would show if this is happening.
The source of the command could be guiding or aligning. If the guiding module has not halted - or a guide function is still running when the flip starts - then the guide command could interfere with the slew that's in progress.
Similarly with alignment, there could be a sync command that is halting the slew.

@Aurneth suggests that a previous align at any time prevents the meridian flip. That's a puzzle but maybe it changes the mount state in some way. Again the mount log will show if the slew should do a meridian flip or not from the actual axis positions.

@Aurneth, log files compress very well, down to 5 to 10% of their original size.

Chris
4 years 3 months ago #46687

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So I've excised the entire log from starting up to failed flip, which is just under 12 minutes. By luck M31 was approaching the meridian so I plate-solved on it and let it go. I've cut nothing from the log for this period.

Here's a brief time line:

19:30 - System turned on, EQMOD Mount + ZWO Guider
19:31:42 - EQMOD instructed to goto M31 via R-click menu in KStars
19:31:43 - Mount slewing
19:32:28/9 - Mount tracking M31
19:32:30+ - Ekos instructed to plate solve, but doesn't show up in the log as far as I can tell
19:33:46 - Some plate solving results come through (n.b. the mount is consistently about 13° off in RA for the initial targeting of objects near the meridian coming out of parked position)
19:33:47 - Slewing after plate solving
19:34:03 - Tracking reengaged
19:34:21 - More plate solving results
19:34:22 - Slewing after plate solving
19:34:23 - Tracking reengaged - appears to be the final alignment correction yet I don't see any more plate solving results after this showing the mount to be satisfactorily aligned
19:41:16 - Meridian flip initiated
19:41:18/9 - Meridian flip "completed"

File Attachment:

File Name: EQMODZWO-F...1207.txt
File Size:986 KB



Next I'll post from a successful flip.
4 years 3 months ago #46689
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Following the above, I parked the mount then disconnected Ekos and stopped INDI before restarting it all again.

19:43:04 - Ekos disconnection
19:43:05 - INDI disconnection
19:43:15 - INDI & Ekos restarted
19:43:44 - EQMOD instructed to goto star to the east of M31 via R-click in KStars
19:43:45 - Mount slewing
19:44:30 - Mount starts tracking
19:45:01 - Here I instruct Ekos to slew to another star closer to the meridian
19:45:02 - Mount slewing
19:45:10 - Mount starts tracking
19:45:46 - Here I instruct Ekos to slew to another star still closer to the meridian
19:45:47 - Mount slewing
19:45:49 - Mount starts tracking
19:47:40 - Meridian flip initiated
19:48:56/7 - Meridian flip completed

File Attachment:

File Name: EQMODZWO-S...1207.txt
File Size:618 KB



I continued carrying out tests for another 90 minutes or so in which I was able to establish that plate solving impeded all subsequent meridian flips in that INDI session.
4 years 3 months ago #46692
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Hi Aurneth,
my theory is still that there is a mismatch in time or geo location between your mount and EKOS. EKOS itself has no influence upon the decision of the mount which pier side is chosen when slewing to a specific target. The assumption of EKOS is that the mount changes the pier side after the target has crossed the meridian when the same target is re-slewed to. That's the entire magic behind the EKOS meridian flip.

When we see that it takes only seconds to slew again to the same target, the mount simply has taken the decision to stay on the same pier side. This is something where EKOS has no influence, it's a decision of the mount firmware. The explanation is that at least for the geo location and time of the mount, this decision is correct - but it does not match with EKOS. So either EKOS has a different time or date set or the geo location do not match - or maybe both.

@Chris, Jasem: do I miss something here? I haven't seen anything unusual here besides the situation that the mount does not always change the pier side as expected. Everything else seems to run fine.

- Wolfgang
4 years 3 months ago #46693

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Hi everyone
JTOL...

The eqmod side if pier was fixed here and has worked perfectly ever since:
github.com/indilib/indi/pull/658

Eqmod users are fortunate in that we have accurate side of pier reporting.

@OP. Is there any way you could get a physical imaging camera to test this with align and eqmod? A DSLR with a lens would be fine.
Is your computer set to receive Internet date and time?
Cheers and HTH
Steve
Last edit: 4 years 3 months ago by alacant.
4 years 3 months ago #46694

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You are right Wolfgang, the meridian flip slew move does not involve a meridian flip. It's possible that the flip has already happened, or that a guide command has blocked it.

The initial position is set here:
[2019-12-07T19:31:42.381 EST DEBG ][ org.kde.kstars.indi] - ISD:Telescope sending coords RA: "00h 43m 49s" ( 0.730369 ) DE: " 41° 22' 45\"" ( 41.3794 )
The mount calculates the slew delta and sends commands:
[2019-12-07T19:31:42.484 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SlewTo() : deltaRA = 2537643 deltaDE = -1218500 "
[2019-12-07T19:31:42.485 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] SetMotion() : Axis = 1 -- dir=forward mode=goto speedmode=highspeed "
...
[2019-12-07T19:31:42.572 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] SetMotion() : Axis = 2 -- dir=backward mode=goto speedmode=highspeed "
This is a fairly large slew and so the motors are commanded to run at high speed.
The slew is completed with a low speed run:
[2019-12-07T19:32:26.249 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] IsRARunning() = false "
[2019-12-07T19:32:26.250 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] CheckMotorStatus() : Axis = 2 "
[2019-12-07T19:32:26.250 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] IsDERunning() = false "
[2019-12-07T19:32:26.259 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SlewTo() : deltaRA = 4588 deltaDE = 0 "
[2019-12-07T19:32:26.259 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] SetMotion() : Axis = 1 -- dir=forward mode=goto speedmode=lowspeed "
And tracking is started:
[2019-12-07T19:32:28.445 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] IsRARunning() = false "
[2019-12-07T19:32:28.445 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] CheckMotorStatus() : Axis = 2 "
[2019-12-07T19:32:28.445 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] IsDERunning() = false "
[2019-12-07T19:32:28.451 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] ResetMotions() "
[2019-12-07T19:32:28.451 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] CheckMotorStatus() : Axis = 1 "
[2019-12-07T19:32:28.452 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":G110\", 6 bytes written "
[2019-12-07T19:32:28.452 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=\", 2 bytes read "
[2019-12-07T19:32:28.452 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] CheckMotorStatus() : Axis = 2 "
[2019-12-07T19:32:28.452 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":G211\", 6 bytes written "
[2019-12-07T19:32:28.452 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=\", 2 bytes read "
[2019-12-07T19:32:28.453 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] StartRATracking() : trackspeed = 15.0411 arcsecs/s, computed rate = 1 "
Then there's a sync:
[2019-12-07T19:33:46.563 EST DEBG ][ org.kde.kstars.indi] - ISD:Telescope: Syncing...
[2019-12-07T19:33:46.571 EST DEBG ][ org.kde.kstars.indi] - ISD:Telescope sending coords RA: "23h 51m 07s" ( 23.8521 ) DE: " 41° 22' 05\"" ( 41.3681 )
[2019-12-07T19:33:46.816 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":j1\", 4 bytes written "
[2019-12-07T19:33:46.816 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=A8C4A1\", 8 bytes read "
[2019-12-07T19:33:46.817 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] GetRAEncoder() = 10601640 "
[2019-12-07T19:33:46.817 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":j2\", 4 bytes written "
[2019-12-07T19:33:46.817 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=BCD38F\", 8 bytes read "
[2019-12-07T19:33:46.833 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[ALIGNMENT] New sync point Date 2458825.523439 RA 23.852100 DEC 41.368100 TDV(x 0.750013 y 0.022445 z 0.661042) "
...
[2019-12-07T19:33:46.846 EST DEBG ][ org.kde.kstars.indi] - ISD:Telescope sending coords RA: "00h 43m 51s" ( 0.731074 ) DE: " 41° 22' 45\"" ( 41.3794 )
And a slew, high speed in RA
[2019-12-07T19:33:46.959 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SlewTo() : deltaRA = -330415 deltaDE = 283 "
[2019-12-07T19:33:46.959 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] SetMotion() : Axis = 1 -- dir=backward mode=goto speedmode=highspeed "
Then a slow slew:
[2019-12-07T19:33:57.678 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] IsRARunning() = false "
[2019-12-07T19:33:57.679 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] CheckMotorStatus() : Axis = 2 "
[2019-12-07T19:33:57.679 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] IsDERunning() = false "
[2019-12-07T19:33:57.689 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SlewTo() : deltaRA = 1046 deltaDE = 0 "
[2019-12-07T19:33:57.689 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] SetMotion() : Axis = 1 -- dir=forward mode=goto speedmode=lowspeed "

There are a series of slow slews through small amounts that I guess are guiding.

Now the meridian flip 'slew'.
[2019-12-07T19:41:16.084 EST DEBG ][ org.kde.kstars.ekos.mount] - Meridian flip planned with LST= "00h 44m 31s" scope RA= "00h 43m 54s" and meridian diff= 0.01
[2019-12-07T19:41:16.084 EST DEBG ][ org.kde.kstars.ekos.mount] - Setting meridian flip status to 1
[2019-12-07T19:41:16.701 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] Compute local time: lst=0.74219640 ( 0:44:31.91) - julian date=2458825.52864834 "
[2019-12-07T19:41:16.701 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":j1\", 4 bytes written "
[2019-12-07T19:41:16.713 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=F46F9D\", 8 bytes read "
[2019-12-07T19:41:16.714 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] GetRAEncoder() = 10317812 "
[2019-12-07T19:41:16.714 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":j2\", 4 bytes written "
[2019-12-07T19:41:16.728 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=51D98F\", 8 bytes read "
[2019-12-07T19:41:16.728 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[SCOPE] Current encoders RA=10317812 DE=9427281 "
[2019-12-07T19:41:16.729 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":f1\", 4 bytes written "
[2019-12-07T19:41:16.754 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=111\", 5 bytes read "
[2019-12-07T19:41:16.754 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":f2\", 4 bytes written "
[2019-12-07T19:41:16.754 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=101\", 5 bytes read "
[2019-12-07T19:41:17.084 EST DEBG ][ org.kde.kstars.ekos.mount] - Setting meridian flip status to 4
[2019-12-07T19:41:17.084 EST DEBG ][ org.kde.kstars.ekos.mount] - Slewing to RA= "00h 43m 52s" DEC= " 41° 22' 45\""
[2019-12-07T19:41:17.094 EST DEBG ][ org.kde.kstars.indi] - ISD:Telescope sending coords RA: "00h 43m 52s" ( 0.731238 ) DE: " 41° 22' 45\"" ( 41.3794 )
[2019-12-07T19:41:17.179 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] StopRA() : calling RA StopWaitMotor "
[2019-12-07T19:41:17.179 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":f1\", 4 bytes written "
[2019-12-07T19:41:17.186 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=111\", 5 bytes read "
[2019-12-07T19:41:17.186 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] StopWaitMotor() : Axis = 1 "
[2019-12-07T19:41:17.186 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":K1\", 4 bytes written "
[2019-12-07T19:41:17.187 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=\", 2 bytes read "
[2019-12-07T19:41:17.187 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":f1\", 4 bytes written "
[2019-12-07T19:41:17.187 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=101\", 5 bytes read "
[2019-12-07T19:41:17.187 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] StopDE() : calling DE StopWaitMotor "
[2019-12-07T19:41:17.187 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":f2\", 4 bytes written "
[2019-12-07T19:41:17.187 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=101\", 5 bytes read "
[2019-12-07T19:41:17.188 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] StopWaitMotor() : Axis = 2 "
[2019-12-07T19:41:17.188 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":K2\", 4 bytes written "
[2019-12-07T19:41:17.200 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=\", 2 bytes read "
[2019-12-07T19:41:17.200 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] dispatch_command: \":f2\", 4 bytes written "
[2019-12-07T19:41:17.202 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[COMM] read_eqmod: \"=101\", 5 bytes read "
[2019-12-07T19:41:17.211 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[DEBUG] SlewTo() : deltaRA = 274 deltaDE = 0 "
[2019-12-07T19:41:17.212 EST DEBG ][ org.kde.kstars.indi] - EQMod Mount : "[MOUNT] SetMotion() : Axis = 1 -- dir=forward mode=goto speedmode=lowspeed "

The movement is very small and is low speed only, a little later tracking is started.
And after that the log stops.

One possibility is that the meridian slew has already happened. The slew at 19:31:42 is a long one in both Ra and Dec.
As for the pier side, I woud expect that there would be more in the log about it there is very litte data other than raw data.

If someone who is more familiar with this driver might be able to get more out of the logs, in particular converting the raw axis positions to hour angle and declination to see if the flip is still needed.

Chris
4 years 3 months ago #46696

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Hi Wolfgang,

Well I'm open to the possibility of some sort of time/geo-based cause as the initial slews to targets well removed from the parking position are off by about 13° W in RA (typically ~47000" is reported in the plate solver). I don't really have a satisfactory idea of why this is. You can see it in the log I posted on slewing to M31 at 19:33:46 where the plate solving reports a location of 23h 51m 07s rather than the 00h 43m 49s of M31's actual position. Would clearing the mount model help?

That said, the times reported in the log upon system initialization are correct, so KStars and Ekos are at least using the correct times. If there were a mismatch with the mount, how would I determine it and how would I correct it?

With respect to location, I've set up KStars with the city of Ottawa, Canada as its location using its default coordinates in the KStars setup wizard. From my phone, it tells me I'm about 6' west and 1' south of those coordinates. Now if I understand the implications of that correctly, with no other data available, the mount would tend to aim slightly west of the true location of an object and thus it would tend to flip slightly *earlier* in time than it would were the precise coordinates known. So how would updating that with information from a plate solve affect it? I've already determined that an HA>0.2h has the same results, and that's more than the time difference introduced by my physical offset from the default Ottawa coordinates.

Given this ~13° initial targetting discrepancy, and given than I've tended to aim for objects fairly close to the meridian to plate solve (it's sort of a site constraint), I suppose there is a possibilty that there is an erroneous determination post-plate solving that the mount has already been flipped, even though Ekos reports a countdown to a pending flip? I guess I could try to initially solve on objects well east of the meridian to remove any possibility of uncertainty as to what side of the pier the mount is on.

But that would have to wait for another clear night, not until Thursday.
4 years 3 months ago #46697

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