I’m guessing this will mainly be a question for one of the Developers.
I use an Alter D6 GEM mount fitted with an AWR drive system together with the driver supplied by Tigra Astronomy.
I’m fairly new to SGP but I’ve been unable to get an automatic meridian flip to work.
Both AWR & Tigra have been extremely helpful & supportive but I need some technical information in deeper detail than that provided in the SGP help files.
My system cannot support a time set before the meridian & SGP correctly warns me of this if I try to do this. In practice I need to set a post meridian delay of say 30 minutes.
The pier flip routine does begin, take an image, stop the guider, complete the JNOW\J2000 conversion etc. I can see it all in the log file. But the mount never actually slews. In the event log it tells me the procedure has failed because the starting side of the pier & the ending side of the pier are the same.
Here is an extract from the uploaded log file:
[10/09/18 21:57:39.415][DEBUG] [Pier Flip Thread] PHD2 GetPhdStatus - Post-Wait: Stopped
[10/09/18 21:57:39.415][DEBUG] [Pier Flip Thread] PHD2: Successfully stopped PHD2…
[10/09/18 21:57:39.415][DEBUG] [Pier Flip Thread] Meridian Flip: Sending Telescope command to execute meridian flip
[10/09/18 21:57:39.454][DEBUG] [Telescope Thread] ASCOM Telescope: Pier side is West
[10/09/18 21:57:39.454][DEBUG] [Telescope Thread] ASCOM Telescope: attempting pier flip using slew
[10/09/18 21:57:39.609][DEBUG] [Telescope Thread] Telescope: Slewing to J2000 RA: 18.8922030571624 (18h53m31.93s) Dec: 33.0155083437973 (33°00’55.83")
[10/09/18 21:57:39.609][DEBUG] [Telescope Thread] Telescope: Slew received J2000 coordinates, mount requires JNOW, converting…
[10/09/18 21:57:39.609][DEBUG] [Telescope Thread] Telescope: Slewing to JNOW RA: 18.9036111111111 Dec: 33.0452777777778
[10/09/18 21:57:43.479][DEBUG] [Telescope Thread] Scope reports it is done with synchronous slew, verifying…
[10/09/18 21:57:43.480][DEBUG] [Telescope Thread] Telescope: Slewing has completed
[10/09/18 21:57:43.480][DEBUG] [Telescope Thread] Telescope: Settling for 3 seconds
[10/09/18 21:57:46.480][DEBUG] [Telescope Thread] Telescope: Settling has completed
[10/09/18 21:57:47.000][DEBUG] [Telescope Thread] ASCOM Telescope: Failed to flip because starting pier side and ending pier side are the same!
[10/09/18 21:57:47.327][DEBUG] [Pier Flip Thread] Meridian Flip: Telescope command to meridian flip has completed
[10/09/18 21:57:47.327][DEBUG] [Pier Flip Thread] Meridian Flip: Telescope failed to perform meridian flipsg_logfile_20181009213158.txt (537.1 KB)
How can this be I ask? When it clearly is not?
I decide to run the ASCOM conform tool which exercises your mount & among many other things conducts side of pier tests as described in the following links to the relevant ASCOM standards documentation:
The subject is quite confusing, if you follow the links you’ll see there are historical reasons why the sideOfPier property name does not reflect it’s true meaning. My personal conclusion is that there may even be a mistake in the ASCOMSideOfPierBehaviour.pdf paper?
Anyway, the result of my conform test was that my mount reports the physical side of pier rather than the pointing state - which is flagged up as an issue at the end of the report.
Tests I’ve carried out using a terminal application to poll the mount (:GSP#) returns E when my scope is on the west side of the pier pointing east but this does not change when the scope crosses the meridian - which is not what I expected. It only changes if I perform a GOTO or a slew over the pole.
This is why I think I see the failure message “Telescope: Failed to flip because starting pier side and ending pier side are the same!” in the SGP log file.
I’m currently liaising with AWR & Tigra who are both give fantastic support but regarding SGP I’d like to ask the following questions:
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How do the developers view\interpret the sideOfPier property?
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Do you consider the ASCOMSideOfPierBehaviour.pdf paper is correct?
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Does SGP specifically require the mount to return it’s pointing state or can the automatic pier flip be made
to work with mounts that only report the physical side of pier? -
How does SGP actually instruct the mount to flip? Does issue a GOTO\slew to the current coordinates?
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Perhaps an obvious question but if the scope is on the west, pointing east & mount tracks across the
meridian naturally from east to west (the weights now point up), scope is on the west but now pointing
west would SGP expect to see a change in the sideOfPier property? I.E should the flag change from E to W?
PS
I’d also be interested to hear from anyone else who uses an AWR drive system.