Author Topic: Pier flip  (Read 67273 times)

Offline gpaolo

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Pier flip
« on: Friday, 06.09.13 - 09:00:29 - CEST »
Hi,
I'm trying to use CCD Autopilot to control the CCD and I'm having a problem related to the pier flip.
I explain what I did tonight, maybe it's the best way to understand the problem...

I started the observation with the telescope west looking east, after the unpark command.
I did the guide calibration, everything went fine, but when I begun to guide, the Y axis moves in the opposite direction.
By connecting the scope to Maxim, I noticed that the pier flip status was active, while I never performed any pier flip.
If I change the scope direction on the LFEP control panel, from west looking east to east looking east, the guide begins to work and the pier flip status disappear, so it is a problem definitively related to that.
If instead than starting with the scope west looking east I perform the calibration with the scope east looking west (no pier flip status active), the guide also works.

So my idea is that the program performs the guide calibration thinking to be in normal condition (no pier flip) but, when it comes the moment to guide, it sees that the telescope has the pier flip active and it decides to reverse the Y axis.

I thought that the pier flip status should be active only when the pier flip is performed, not "by default" with the scope west looking east -which doesn't have much sense to me, because you must flip going in east-west direction, not on the other way. Do you know if there is any way to reset this status so that the controller will stop telling to the control program to reverse the guide direction?

Offline the_lizardking

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Re: Pier flip
« Reply #1 on: Friday, 06.09.13 - 13:50:44 - CEST »
I think this more a bug... I will also try today,... and let you know.

Offline gpaolo

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Re: Pier flip
« Reply #2 on: Friday, 06.09.13 - 14:00:04 - CEST »
I'm not sure if it is a bug or a misconfiguration. Since my LFEP is of 2nd hand, I don't know if the previous owner made some special configuration for its setup.
Next time I have a clear night, I would like to try to set it up as it is, perform a meridian flip to make the flag change, then manually move the telescope on the other side and synchronize it again.
In any case, I would be grateful if you can check. As I said, telescope west looking east --> pier flip active, telescope east looking west --> pier flip not active, it is the opposite of what should be.
If it turns out that it is a bug, maybe through the ASCOM interface would be possible to add a switch to reset the status of the flag.

Offline Armando

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Re: Pier flip
« Reply #3 on: Friday, 06.09.13 - 14:13:15 - CEST »
Hi gpaolo,

if you're using MaxIm DL you can try to make use of ASCOM Inverted mode as Side of Pier (if you're having issues by ASCOM normal mode): you can select it by Observatory setup tab (in Telescope options).
I hope it helps.

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #4 on: Friday, 06.09.13 - 14:16:25 - CEST »
Thanks Armando, I will check it out!
Unfortunately, I don't think it is a maxim problem...
When I work only with Maxim, everything is fine. The issue comes when I try to use CCD Autopilot, which overwrites Maxim setup with its own to handle the pier flip. So, when the LFEP tells CCD Autopilot that the pier flip status is active, CCD Autopilot automatically reverse the Y direction of the guide.

Offline Armando

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Re: Pier flip
« Reply #5 on: Friday, 06.09.13 - 15:05:18 - CEST »
Hi gpaolo,

there is no flipped event or any ASCOM property related to it: the only ASCOM method to be taken into account is SideOfPier. And I think it works as expected.
I would expect guiding working without any issue soon after a calibration regardless of SideOfPier if no GoTo commands occur...

I don't use CCD AutoPilot but I would suggest to check its settings.

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #6 on: Friday, 06.09.13 - 15:30:00 - CEST »
I spent more than four hours tonight trying any setting in CCD Autopilot and unfortunately it relies completely on the informations received by the controller...
So, if there is no ASCOM event or property related to pier flip, how could I see the pier flip information in Maxim when I connect the telescope and just be able to change it by switching the side of the telescope in the ASCOM panel? Is it possible that it is calculated by Maxim itself? I don't really know how it works, I though that it was something determined by the controller...

Offline Armando

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Re: Pier flip
« Reply #7 on: Friday, 06.09.13 - 15:41:42 - CEST »
So, if there is no ASCOM event or property related to pier flip, how could I see the pier flip information in Maxim when I connect the telescope and just be able to change it by switching the side of the telescope in the ASCOM panel?
I think the PierFlip command should work exactly as the ASCOM LFEP Flip button: it's enabled when a flip is opportune.

Quote
Is it possible that it is calculated by Maxim itself?
Yes, according to SideOfPier returned by ASCOM driver on request by the ASCOM client (MaxIm or maybe CCDAutoPilot if it also communicates directly to LFEP by its own ASCOM connection in your case).

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #8 on: Friday, 06.09.13 - 15:53:03 - CEST »
So, if there is no ASCOM event or property related to pier flip, how could I see the pier flip information in Maxim when I connect the telescope and just be able to change it by switching the side of the telescope in the ASCOM panel?
I think the PierFlip command should work exactly as the ASCOM LFEP Flip button: it's enabled when a flip is opportune.

Ok, understood, but in this case I'm talking of the pier flip status, I mean the flag that indicates that the telescope has been flipped.

Quote
Is it possible that it is calculated by Maxim itself?
Yes, according to SideOfPier returned by ASCOM driver on request by the ASCOM client (MaxIm or maybe CCDAutoPilot if it also communicates directly to LFEP by its own ASCOM connection in your case).
[/quote]

Understood. So, if it turns out that it is a bug, would it be possible to instruct the ASCOM interface to return the opposite value of SideOfPier?

Offline Armando

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Re: Pier flip
« Reply #9 on: Saturday, 07.09.13 - 01:38:34 - CEST »
Quote
Understood. So, if it turns out that it is a bug, would it be possible to instruct the ASCOM interface to return the opposite value of SideOfPier?
I'm tempted to think that by this change a flip event would still be detected by CCDAutoPilot (even if not occurred) when starting from the opposite side...  ::) Am I wrong?

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #10 on: Sunday, 08.09.13 - 18:59:42 - CEST »
I don't know, I thought that the pier flip was an event indicated by the controller only when the flip occurred, but instead it seems to be a status depending on the combination of the telescope position. In my case, this status is active on the wrong side (telescope west looking east).

Offline Armando

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Re: Pier flip
« Reply #11 on: Sunday, 08.09.13 - 19:45:23 - CEST »
Hi gpaolo,

you can find the following instructions at http://www.ccdware.com/help/ccdap5/hs220.htm :
Quote
Maxim-specific requirements: Go to the Camera Control window, hit the Settings button to bring up the Guider Settings window. Select the Advanced tab. Under Guider Motor Control, make sure to select Do Not Change On Pier Flip. Do not check Pier Flip on the Camera Control Window/Guide tab.  If you connect to your telescope in Maxim's Observatory window, be sure to uncheck Auto Scope Dec., Pier Flip and Auto Pier Flip. CCDAutoPilot manages all necessary meridian flip issues internally and allowing Maxim to make flip-related changes will most likely cause guiding problems. A telescope connection is required to use pulse guide, called "Telescope" in Maxim's Autoguider Output Control Via selection. When using the Telescope guide option, It may be helpful to check Safety Slew on the Guiding page, Meridian Flip box of CCDAutoPilot.
Maybe it helps to solve the issue.

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #12 on: Sunday, 08.09.13 - 20:30:55 - CEST »
No, unfortunately it doesn't. It is one of the first things I checked.
What I understand is:
- CCDAP makes calibration assuming that the telescope is in normal setup (no flipping)
- When CCDAP starts guiding, it checks the telescope status and receives the pier flip information (even if no flip has ever occurred) and sets the guiding axis accordingly
- Guide star is inevitably lost...


Offline Armando

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Re: Pier flip
« Reply #13 on: Sunday, 08.09.13 - 20:57:15 - CEST »
Hi gpaolo,
No, unfortunately it doesn't. It is one of the first things I checked.
What I understand is:
- CCDAP makes calibration assuming that the telescope is in normal setup (no flipping)
- When CCDAP starts guiding, it checks the telescope status and receives the pier flip information (even if no flip has ever occurred) and sets the guiding axis accordingly
- Guide star is inevitably lost...
this is the reason why I think that reversing the PierSide returned by ASCOM will cause the same issue when starting on the opposite side (that now causes you no issues...).
Maybe it's a CCDAP bug...

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #14 on: Monday, 09.09.13 - 00:56:30 - CEST »
Maybe... but you could choose in this way how to configure the pier flip status.
In any case, as far as I know, right now the pier flip status is inverted on my LFEP: with the scope on west looking east, it should not be active.

Offline Armando

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Re: Pier flip
« Reply #15 on: Monday, 09.09.13 - 12:04:10 - CEST »
Maybe... but you could choose in this way how to configure the pier flip status.
By returning a wrong PierSide???

Quote
In any case, as far as I know, right now the pier flip status is inverted on my LFEP: with the scope on west looking east, it should not be active.
You mean wrongly "computed" and shown by the software you're using, according to the right PierSide returned by ASCOM driver...

Just to know, is the mount already aligned (I mean with a sync command occurred) before starting CCDAP?

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #16 on: Monday, 09.09.13 - 12:09:52 - CEST »
Quote
You mean wrongly "computed" and shown by the software you're using, according to the right PierSide returned by ASCOM driver...

No, I'm not getting the right pier side, I'mgetting the wrong pier side now. It is the opposite of what should be, that is the problem.
With the scope west looking east I get the pier flip active, while there is no way that I can perform the pier flip in this configuration.

Yes, the telescope is synchronized at program startup.



I was thinking, is it possible that the LFEP is configured to think to be in the wrong hemisphere? In that case, west looking east would require the pier flip...

Offline Armando

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Re: Pier flip
« Reply #17 on: Monday, 09.09.13 - 13:20:39 - CEST »
Hi gpaolo,
No, I'm not getting the right pier side, I'm getting the wrong pier side now. It is the opposite of what should be, that is the problem.
With the scope west looking east I get the pier flip active, while there is no way that I can perform the pier flip in this configuration.
If the issue is related to a wrong PierSide then you need to be sure Dec motor direction is properly set.
So by a click on ASCOM handbox InvertDec button you can set the right/current PierSide; then you can send a GoTo command. If it makes the mount moving on Dec in the wrong direction you have to change Dec direction setting (you find it by LFEP ASCOM Telescope setup - Motors tab).
Maybe this is the reason of the troubles...

CS
Armando

Offline gpaolo

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Re: Pier flip
« Reply #18 on: Monday, 09.09.13 - 13:25:02 - CEST »
Ah! Ok, thanks! That sounds like a very promising suggestion! As soon as I can install again the telescope (damn weather...) I will try it!  ;)

Offline gpaolo

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Re: Pier flip
« Reply #19 on: Tuesday, 10.09.13 - 20:10:20 - CEST »
I'm making some tests right now but there is definetively something that I'm missing...
This is the position of the telescope:



as you can see, the telescope would be on the west side of the pier, looking towards east. For me, this is the only sure thing.

In this position, to avoid to have the "pier flip" indicator active, I have to tell the ASCOM driver that the telescope is EAST looking east, which is quite false:



and I have to invert the DEC motor direction to make it moving correctly.
Note that, in this way, the flip telescope is not active: to be able to use it, I have to press the InvertDEC button, to have the telescope west looking east (as it really is), but when the mount performs the flip, the DEC axis is moving on the opposite side!
This is quite a mess...
Any idea?