Re: APCC with SGP Pier Flip Failure #APCC

Luca Marinelli

In the APCC window, uncheck limit to Meridian or the meridian limits you setup are ignored by APCC. You may then have a situation were SGP has no time to execute the flip before the mount stops tracking. If the mount stops tracking, SGP will abort the sequence.


On Sep 21, 2021, at 9:16 PM, Luca Marinelli via <> wrote:

I don’t doubt that you are having meridian flip related sequence failures. However, I will offer the datapoint that I am using SGP 4 v680 with both an AP 1100 and Mach2 without any meridian flip failures.

I have set up the meridian limits and set the flip offset to at least 5 minute more than my longest exposure in the sequence (for example, if the sequence has 10 minute exposures I set the flip offset to 15 minutes). I set the action at the meridian limit to stop tracking (SGP calls the slew that initiates the flip and it should always happen at least 5 minutes before the actual limit with the above flip offset). Check the box to pass flip offset to SGP and I also check the box for CW up slews within West limits.

Nothing unusual in the SGP telescope setup window. I just enable auto meridian flip and check the box to perform a centering action after the flip. No need to mess with the time after meridian to flip because APCC passes that parameter along dynamically with the flip offset.


On Sep 21, 2021, at 8:29 PM, Ray Gralak via <> wrote:
What are the settings on APCC's meridian limits tab?
E.g., Are meridian limits enabled? What flip offset do you have defined? Etc.
-----Original Message-----
From: [] On Behalf Of psparkman via
Sent: Tuesday, September 21, 2021 4:21 PM
Subject: [ap-gto] APCC with SGP Pier Flip Failure #APCC
Greetings. I posted this on SGP forum as I think the issue is mostly on their end, but thought that I would
also post it here for help.
Generally pier flips have been working with SGP and APCC on my AP1100, however last night it
failed an unattended pier flip and aborted my sequence for the night. So I lost about 5 hours of imaging.
It has been working, but I was always worried that I might run into the same issue as I have when I do a
delayed counter weight up pier flip. When using APCC and using the delayed counter weight up functionality,
everything works fine with SGP until the actual flip is commanded. When my AP1100 mount slews from a
counter weight up position it performs a “Safety Slew”. First the mount only moves in RA to get to a counter
weight up position as this prevents the dec from rotating the scope into pier. The mount pauses for a couple
of seconds after the RA has moved to counter weight level before it starts the move the requested RA/DEC or
pier flip.
This is when I think the problem occurs. SGP thinks that the mount has already completed the slew and gives
the error that the scope is still on the West side of the pier due to this delay. I currently have the pier flip delay
set to 1 min past the meridian to prevent the scope from oscillating back and forth during the plate solve after
the pier flip, but it looks like this time the safety slew delay caused SGP to abort. It would be really good to
get this fixed as then I could use the delayed flip feature of APCC and SGP, but at the very least, this needs
to be made reliable with a standard flip.
I have included both log files, and will also post it on AP’s forum. But I don’t want to get caught between two
companies blaming each other. SGP and AP are both premier companies in my mind and I just want to get
this working.
Link to Logs
Useful Info
OS: Windows 10
Ver: SGP 64-bit
APCC Version

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