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INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

Side-of-pier problem - bug?

2 months 2 weeks ago 2 months 2 weeks ago by Herrhausen.
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Side-of-pier problem - bug? #52283
Magnus, my latest message was in reply to Chris' posting.

An earlier message where I reported an unexpected pier side change at HA -00h 41m 00 could be related to your problem.

The flip issue just came up during the tests that Chris had asked for.

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2 months 2 weeks ago
mlarsson
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Side-of-pier problem - bug? #52284
Great, just good to be clear about it. My issue is quite confusing and seemingly something few users of Losmandy G11 recognize.... but it severely ruins my variable sequences.

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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2 months 2 weeks ago 2 months 2 weeks ago by ChrisRowland.
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Side-of-pier problem - bug? #52286

Herrhausen wrote: It took me a while to figure this flip thing out. I hope I got it. I've set the Gemini "Set Go To:" parameter to 90 and Ekos' "Flip if HA>" to 1 degree (4 minutes).

I cold started Gemini, started Ekos and found the pier side changes at HA -06h00m00s. It's WpE at -05h and EpW at -07h. (This is what I would expect, no?) [Ah, forgot to mention it changes pier side regardless of tracking or slewing]

This is wrong. The Pointing State (aka Pier Side) must not change as a result of normal tracking.

As for tracking through the meridian what I'm looking to see is how the mount behaves when EKOS does not command a pier flip. Once again the Pointing State must not change as a result of tracking through the meridian.

At present the Ekos meridian flip does not use the Pointing State but I've just submitted a patch for Ekos where the pier flip can be managed by reading the Pier Side. It defaults to the current system when Pier Side is not available but if it's reported wrongly then things are unlikely to work properly.

Part of the reason for the additional tests is to see if there are other places where Lasmandy have got it wrong.

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2 months 2 weeks ago
mlarsson
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Side-of-pier problem - bug? #52322
Hi!

Would this patch affect my issue? And can I help by testing it in any particular way? I run Ekos on Stellarmate, so would need to update it to get the patch, I guess (update_indi_drivers?)

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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2 months 2 weeks ago 2 months 2 weeks ago by Herrhausen.
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Side-of-pier problem - bug? #52328

ChrisRowland wrote:

Herrhausen wrote: It took me a while to figure this flip thing out. I hope I got it. I've set the Gemini "Set Go To:" parameter to 90 and Ekos' "Flip if HA>" to 1 degree (4 minutes).

I cold started Gemini, started Ekos and found the pier side changes at HA -06h00m00s. It's WpE at -05h and EpW at -07h. (This is what I would expect, no?) [Ah, forgot to mention it changes pier side regardless of tracking or slewing]

This is wrong. The Pointing State (aka Pier Side) must not change as a result of normal tracking.


So we have a problem.


[IMO Gemini just reports what physically happens as the pier side actually does change here]

As for tracking through the meridian what I'm looking to see is how the mount behaves when EKOS does not command a pier flip. Once again the Pointing State must not change as a result of tracking through the meridian.


In this case the mount does what you expect it to do.

Attachments:

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2 months 2 weeks ago
mlarsson
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Side-of-pier problem - bug? #52342
Hi!

Let me confirm that I have exactly the situation in your first movie. Although I am not certain that it is exactly at 6:00 that my side of pier shifts, but roughly there. G11, Gemini 2.

Best

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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2 months 2 weeks ago
mlarsson
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Side-of-pier problem - bug? #52488
Hi!

If I get it right, side-of-pier as such is dependent only on dec, as described in this document:

ascom-standards.org/Help/Platform/html/P...opeV3_SideOfPier.htm

If I understnad it correctly, that definition means that If I point my scope to the intersection of the equatorial equator and my meridian, that is the mechanical dec/HA zero. Let's say I then have the scope in east position (side-of-pier is east). If I then slew in Dec only, following the meridian, the side-of-pier should shift when crossing the celestial pole, that is going beyond Dec +90 - even without the mount moving in RA.

Is that correctly understood?

My G11 with Gemini 2 does not do that. When I slew following the meridian, cross the celestial pole - without moving in RA (careful, else it does flip when I cross the pole) - the side-of-pier state does NOT change.

However, side-of-pier shifts when I slew in RA but not in Dec, as described before.

Is it correctly understood that this means that the side-of-pier reported by the Gemnii does NOT follow the defintion given in the document I linked to above?

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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2 months 2 weeks ago 2 months 2 weeks ago by ChrisRowland. Reason: add a bit more
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Side-of-pier problem - bug? #52492

mlarsson wrote: Hi!

If I get it right, side-of-pier as such is dependent only on dec, as described in this document:

ascom-standards.org/Help/Platform/html/P...opeV3_SideOfPier.htm

If I understnad it correctly, that definition means that If I point my scope to the intersection of the equatorial equator and my meridian, that is the mechanical dec/HA zero. Let's say I then have the scope in east position (side-of-pier is east). If I then slew in Dec only, following the meridian, the side-of-pier should shift when crossing the celestial pole, that is going beyond Dec +90 - even without the mount moving in RA.

Is that correctly understood?


Yes, that's correct, except that as the mount moves in Dec only as the Dec goes through +90 and the pier side changes then the hour angle will change by 2 hours even though the Ha Axis has not moved. In your case the Ha will go from about 0h to about 12h. It happens at any hour angle. I see exactly this with my Celestron AVX mount.


My G11 with Gemini 2 does not do that. When I slew following the meridian, cross the celestial pole - without moving in RA (careful, else it does flip when I cross the pole) - the side-of-pier state does NOT change.

However, side-of-pier shifts when I slew in RA but not in Dec, as described before.

Is it correctly understood that this means that the side-of-pier reported by the Gemnii does NOT follow the defintion given in the document I linked to above?

Magnus

Also correct.

The ideal solution would be to read the Dec axis position and use that to get the pointing state as i did for the iOptrom mounts. Well second from ideal , the really Ideal solution would be for Losmandy to fix their mount. Has anyone contacted them?

But there's another possibility, from what you described when the mount is pointing in the Southern half of the sky, from Ha -6h to 0 to +6h the mount reported pointing state is correct and when the mount is pointed towards the northern half of the sky with an Ha in the range +6h to +12h/-12h to -6h the pointing state is reversed. Close to -6h and +6h the state reported is indeterminate because the change may not happen at exactly 6h.

This means we could have a software triumph over hardware, where this is implemented in the driver. It reads the pier side from the mount, gets the Ha from the current Ra, longitude and time and uses these to generate the correct pointing state.

Is there someone who want to take this on? Preferably someone with a Losmandy mount who can develop Indi software.

Or I could if there's no one who can, we would need to play the same sort of games as we did over the last few days for the iOptron mounts.

Edit:
I had a look on the Losmandy site and it is all set up nicely with copious ability to report problems and a couple of forums.
They say that the mount reports physical pier side in other words where the scope is when you look at it and this will changes exactly as we have found.
It was fixed in the ASCOM driver six years ago, almost certainly with similar code to what I'm suggesting.

Chris

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2 months 2 weeks ago
mlarsson
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Side-of-pier problem - bug? #52500
Hi!

Thanks for a very clear description, and for veryfying how it is over here (I was almost going mad, for real, for my inability to understand if it was my confusion or a real issue here).

I've raised the issue on the Losmandy user list, but so far not really been able to describe it. I have not contacted Losmandy directly, though.

As for your edit: I can not develop, although I do have a G11 mount. I would be more than happy to assist in any way I can. What would you suggest I do? Try to mobilize Losmandy, or what?

Detail: do you have a link to where it is said about the physical side of mount and fixed in Ascom code? Probably that fix is why noone else recognizes this, because they use ASCOM.

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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2 months 2 weeks ago
alacant
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Side-of-pier problem - bug? #52502
Hi

Not sure if this will help but we had a similar problem with eqmod a while back. The test scenario using PHD2 (which responds correctly to whatever side of pier it is given) and indi_getprop
with the correct outcomes is described here:
linuxcostablanca.blogspot.com/2018/07/indi-eqmod-testing.html

HTH

ubuntu 18.04
700d, eq6, t7m

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2 months 2 weeks ago
ChrisRowland
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Side-of-pier problem - bug? #52507
Magnus,
From what I can see there's little point in contacting Losmandy about this, they have decided to report the physical pier side and the ASCOM driver is already using this so it won't get changed. Easier for us to cope and knwing that's what they are doing helps.

I should be able to persuade Jasem to accept some changed code so all you will need to do is install from a nightly build.

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2 months 2 weeks ago
mlarsson
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Side-of-pier problem - bug? #52509
Chris,

Wonderful! Just tell me if you need some specific testing, or access to my G11 remotely, and I'll do what I can.

Magnus


C8, Losmandy G11, Canon 1000D astromodified.

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