×

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

Bi-monthly release with minor bug fixes and improvements

Re:Figuring out a meridian flip?

  • Posts: 51
  • Thank you received: 0
I have been doing some experimenting with the meridian flip for the past few days. I have found that the meridian line on the Kstars map does not match the HA displayed in the Ekos telescope window. It can be a few minutes off. Also the telescope meridian flip point can be several degrees from the actual telescope meridian point and several degrees from the Kstars/Ekos meridian. To enable an automatic meridian flip, an object must be selected that is East of meridian for both the telescope mount and Ekos. And the flip is executed successfully only if the mount is West of the mount meridian point when the meridian flip goto command is sent to the mount.

Things to do to investigate the issue:
1) In Kstars select an object just East of the meridian line and note the HA time when that object actually crosses the line. HA = 0 is the reference time for the triggering of the goto command that causes the meridian flip. The goto command is sent to the mount when the HA>xx limit is reached.
2) Manually move the telescope with the hand controller or the Kstars telescope movement controls to the point where the counterweight bar is perfectly horizontal. The difference between the telescope location and the meridian line on the Kstars map can be determined by noting the RA position of the cursor on the map in the lower right corner of the map. This may not be the telescope meridian flip point.
3) To determine the telescope mount meridian flip point. select an object sufficiently far to the East that causes the mount to slew to that object with the telescope on the West side of the mount. Periodically press the Kstars goto button until the mount actually does the flip. Watch the HA position in the Ekos telescope window and note the HA position when the flip occurs.
3 years 10 months ago #53715

Please Log in or Create an account to join the conversation.

  • Posts: 554
  • Thank you received: 138
What version of KStars are you using? Hy and I have been working on the meridian flip process recently and it will now retry if the flip falis. It also reports the pier side in the mount tab and can implement a HA limit that is intended to stop the mount tracking into the pier if it is in the wrong pointing state. This may all only be in the sources, not a released version at present. It all requires that the mount reports the pier side. If is doesn't none of this will be done.

in your section 2 some mounts report the mount axis positions. It may be worth watching the Ha or Ra axis position as the mount moves through the meridian. I would expect it to move through 180 or 0/360 degrees at that point. I would esxpect that the target pier side would change as the axis direction goes through 180 or 0.
3 years 10 months ago #53716

Please Log in or Create an account to join the conversation.

  • Posts: 51
  • Thank you received: 0
Kstars: 3.4.2

My primary mount is a Celestron AVX. I don't think it reports HA or the pier side.

I have been doing the testing during the daytime without a doing an accurate alignment to real objects. Some of the differences between the mount and Kstars/Ekos should be reduced after doing a real alignment with stars.
3 years 10 months ago #53774

Please Log in or Create an account to join the conversation.

  • Posts: 554
  • Thank you received: 138

The AVX definitely reports pier side. Ha is always derived from the mount Ra, the time and the longitude. I have one and made sure that the driver uses the mount pier side command.
The following user(s) said Thank You: Paul Muller
3 years 10 months ago #53787

Please Log in or Create an account to join the conversation.

  • Posts: 86
  • Thank you received: 10
did you ever have success with this. I am having issues much like you list but with an ioptron cem60. it does seem to report pier side, but the meridian flip fails .
3 years 9 months ago #55654

Please Log in or Create an account to join the conversation.

  • Posts: 1009
  • Thank you received: 133
Also CEM60 here (EC model, as you might recall from CN...). For me, the flips really work like a charm now. Which version are you running, what are your MF settings, and where does it fail?
3 years 9 months ago #55661

Please Log in or Create an account to join the conversation.

  • Posts: 86
  • Thank you received: 10
yep, thanks for trying to help me.

I think I have everything set in ekos ok, but it crashed and I couldn't capture where exactly it failed, but I remember in the telescope module it said flip failed.

does the cem60 hand control have to also be set to flip vs stop ?? if so, that may be the issue. I had set the hand control to stop, so that if it did do a meridian flip I would know it was ek0s that did it.
3 years 9 months ago #55666

Please Log in or Create an account to join the conversation.

  • Posts: 1009
  • Thank you received: 133
The HC/mount should probably be set to 'stop', but with a limit larger than that used for EKOS. And EKOS should be set to a value somewhat larger than zero, to make sure that the pointing is definitely past the meridian, so that the slew command EKOS sends initiates the move to the other side.
If the mount stops, or starts the flip by itself, any sequence running in EKOS will abort. So the basic idea is that EKOS acts before the mount, and it doesn't really matter what the mount would do...
3 years 9 months ago #55669

Please Log in or Create an account to join the conversation.

  • Posts: 1119
  • Thank you received: 182
Chris recently updated the iOptron driver that is used by the CEM60 and by the iOptronSmartEQPro+. I tested it extensively, since I also had Meridian Flip problems before. I can attest that it works great now, but it may still be available only from sources.

One other thing I learned while testing that revised driver is that the iOptron calculates sidereal time in a confusing way. So while the INDI Control Panel shows the time zone offset correctly, the hand controller may negate that, since it uses a DST setting, and if you forgot to change that when daylight savings time went into effect, your mount will be 15 degrees off and that will be enough to send it into the pier or tripod and have the flip occur at the wrong time.

I would check that first, it could fix a lot of your problems. Make sure time zone and DST settings are correct.

Embarrassingly, mine were wrong....

Jo
Last edit: 3 years 9 months ago by Jose Corazon.
3 years 9 months ago #55673

Please Log in or Create an account to join the conversation.

  • Posts: 86
  • Thank you received: 10
ok thanks. I am pretty sure I am good on times, Ekos did try to start the flip but it failed. I will try setting the hand control to flip instead of stop at 15 degrees past and will set Ekos to flip at 5 degrees past and see what happens. the time Ekos says it will be until the flip seemed correct. I a, using 1.5.3 stellarmate and there are newer stable updates.
3 years 9 months ago #55676

Please Log in or Create an account to join the conversation.

  • Posts: 1957
  • Thank you received: 420
Ekos doesn’t issue a meridian flip. It issues a goto and the mount decides whether it will do a meridian flip or not. So you need to set the mount to a lower value than Ekos otherwise the meridian flip will not succeed. So better set the handcontroller to, say, 5 degrees past and Ekos to, say, 7.5 and see if it goes ok then.


Clear skies, Wouter


Forget what I wrote.


Wouter
Last edit: 3 years 9 months ago by Wouter van Reeven.
3 years 9 months ago #55677

Please Log in or Create an account to join the conversation.

  • Posts: 1119
  • Thank you received: 182

Wouter, are you sure that is correct? Because if that were the case, I should not be able to change the flip time in the mount control tab of the panel. But I can and the flip occurs when I set it in the panel.
I have set the flip time to 3 degrees past the meridian in the mount, so it will not flip prematurely. I usually have Ekos flip at 2 degrees past.
Jo

PS: Also, it would not be possible to wait for an image capture to be completed, the mount would just randomly flip whether capture is finished or not.
Last edit: 3 years 9 months ago by Jose Corazon.
3 years 9 months ago #55679

Please Log in or Create an account to join the conversation.

Time to create page: 1.305 seconds