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INDI Library v1.7.8 Released (11 May 2019)

Mid year release of INDI Library v1.7.8 comes with a few drivers and improvements to to existing drivers.

Mount doesn't complete the meridian flip

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Mount doesn't complete the meridian flip was created by JCJ

I am using KStars v.3.2.3 on a Mac to control a Celestron CGE Pro mount permanently installed in a dome.
While the meridian flip is executed perfectly using the scope simulator and the dome simulator, I meet some issue with my real equipment.
INDI drivers :
- Name=Celestron GPS, exec=indi_celestron_gps v.3.2
- Name=MaxDome II, exec=indi_maxdomeii v.1.3
When the target comes near the meridian :
- the dome moves from West to East
- the mount STARTS the flip but doesn't execute it completely (it comes back immediately to its initial position and doesn't move from West to East)
- as a consequence the dome comes back to its initial West position.
I tried all the possible settings on my Nexstar+ hand control (Favor Current, Favor West, Favor East, Disabled) to no avail.
Is this a problem linked to the indi_celestron_gps v.3.2 driver ?
6 days 4 minutes ago #40065

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Replied by sterne-jaeger on topic Mount doesn't complete the meridian flip

The meridian flip executes a slew to it's last position as soon as the position's hour angle exceeds the meridian by the given amount (by default 0, i.e. as soon as the mount position crosses the meridian). Now it depends upon the behavior of the mount. Typically, a mount should change the pier side if the position has crossed the meridian.

One typical problem is that the time or geo position of KStars and the mount are different. You can simulate the meridian flip yourself.
  1. Turn off the meridian flip in KStars
  2. Slew to a position slightly east of the meridian (hour angle < 0)
  3. Wait until the position crosses the meridian (hour angle > 0)
  4. Issue another slew command to the same position
If no meridian flip takes place, your mount does not consider it as necessary. Check, what is the reason for it.

- Wolfgang
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5 days 17 hours ago #40069

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Replied by knro on topic Mount doesn't complete the meridian flip

JCJ wrote: I am using KStars v.3.2.3 on a Mac to control a Celestron CGE Pro mount permanently installed in a dome.
While the meridian flip is executed perfectly using the scope simulator and the dome simulator, I meet some issue with my real equipment.
INDI drivers :
- Name=Celestron GPS, exec=indi_celestron_gps v.3.2
- Name=MaxDome II, exec=indi_maxdomeii v.1.3
When the target comes near the meridian :
- the dome moves from West to East
- the mount STARTS the flip but doesn't execute it completely (it comes back immediately to its initial position and doesn't move from West to East)
- as a consequence the dome comes back to its initial West position.
I tried all the possible settings on my Nexstar+ hand control (Favor Current, Favor West, Favor East, Disabled) to no avail.
Is this a problem linked to the indi_celestron_gps v.3.2 driver ?


What's the meridian hour angle set to? Maybe it was set to less than the threshold of the mount's meridian flip limit?

What I mean by this is that you can configure your mount to flip only if it is 3 degrees WEST of the meridian. So if Ekos was configured to issue the command 0.1 hours after the meridian, this translates to (0.1*15) = 1.5 degrees, so when Ekos commands the mount to flip, the mount is not yet ready to flip to the other side of the meridian. So you need to double check this difference.
Jasem Mutlaq
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5 days 7 hours ago #40086

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Replied by JCJ on topic Mount doesn't complete the meridian flip

You are right Wolfgang : KStars and the INDI driver work as planned.
.... but I still have to learn how to master my scope more deeply !
Thank you
5 days 6 hours ago #40094

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Replied by JCJ on topic Mount doesn't complete the meridian flip

You are right Wolfgang : KStars and the INDI driver work as planned.
.... but I still have to learn how to master my scope more deeply !
Thank you
5 days 6 hours ago #40095

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Replied by JCJ on topic Mount doesn't complete the meridian flip

Here are my settings :
- The meridian hour angle is set to zero : Flip if HA > 0.00 h
- The RA Limits are disabled
- If Meridian Favor Current : no flip when object crosses meridian
- If Meridian Favor West : no flip when object crosses meridian
- If Meridian Favor East : no flip when object crosses meridian
- The flip only occurs if the Meridian is changed from Favor West to Favour East AFTER the telescope slewed to the focused object
I am using a NexStar+ hand control.
Last edit: 4 days 22 hours ago by JCJ.
4 days 22 hours ago #40100

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Replied by ChrisRowland on topic Mount doesn't complete the meridian flip

When the Ra limits are disabled there are still limits of 20 degrees before and 20 degrees after the meridian.

The meridian mode controls how the mount responds to slew commands when it is close to the meridian.

Favour West will cause a slew to use the West pointing state if the object is less than 20 degrees east of the meridian, so it will slew using the West pointing state if the object is within 1 hour 20 mins of the meridian. it will slew early.
Favour East will use the East state until the object is 20 degrees after the meridian, it will flip late.

For the range from 20 degrees before to 20 degrees after the meridian you can use either pointing state, using favour east or favour west to choose which side.

If you set favour current it will do what you ask and not do a flip.

To get a flip at the meridian you need to turn the meridian mode off. AND you also need to set the flip position in Ekos to a little after the meridian so there is no debate about if the mount thinks it has crossed the meridian.

I use the meridian mode to handle the ASCOM set SideOfPier behaviour.
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4 days 21 hours ago #40101

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Replied by JCJ on topic Mount doesn't complete the meridian flip

Thank you for this extensive reply.
I disabled the meridian on my hand control and set the Ekos flip to HA > 0.1 h to be sure.
When the object crossed the meridian + 0.1 h, Ekos said : "Meridian flip planned..." but no flip occurred (even not the beginning of a flip as it used to be).
May be my NexStar+ hand control is corrupted ?
(HC + MC firmware version: HC: GEM 5.31.9102 MC: 6.17 6.17)
Last edit: 4 days 20 hours ago by JCJ.
4 days 20 hours ago #40104

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Replied by sterne-jaeger on topic Mount doesn't complete the meridian flip

Is a capture sequence running? Planned means that the mount waits until the next capture is completed.
4 days 20 hours ago #40105

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Replied by JCJ on topic Mount doesn't complete the meridian flip

No there is no capture sequence running.
I am using the Ekos Mount panel to test the meridian flip.
4 days 20 hours ago #40109

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Replied by sterne-jaeger on topic Mount doesn't complete the meridian flip

Hm, strange. Please post the logs.
4 days 20 hours ago #40110

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Replied by ChrisRowland on topic Mount doesn't complete the meridian flip

I would certainly wonder if any command was actually sent to the mount. A full debug log from the mount driver will show the commands to the mount. It should also show the pier side response from the mount.
4 days 19 hours ago #40111

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