Guiding lost, end of sequence

[giraud]

Hello Robin,

I was planning for a long session to image M81 last night (with and without filter to compare). I am using the sequence planner.

Everything went fine until after the automatic meridian flip, at around 01h56.
The guiding state became 'Current guiding state is Looping' while running step Start guiding if necessary' at 01:56:59. And at 01:57:31, the sequence started the shutdown process after receiving the message 'PHD2 has been stuck in state Looping for 31s'.

I don't know exactly what happened with the guiding at that moment (couldn't find a star from the PHD2 log attached), but I am wondering how I can make my sequence more robust so that I give much more time for PHD2 to recover the situation (maybe waiting for clouds to disappear).

Many thanks for your support.

Cheers,
Eric.

[admin]

Hi Eric,

looking through the log, it looks like there was an unintended behaviour due to the meridian flip... I think there are a few things all mixing together to make this happen.

As the mount passes the meridian by 1 degree, the 'Stop at -1 from meridian' step halts the main imaging sequence. The way this happens leaves the 'dither every 5 frames' active, since it stops the step in progress (probably capture 30 frames) and doesn't run the steps after that.

Next, the meridian flip subroutine runs, which performs an autofocus - the autofocus is now happening with dithering enabled, but the autofocus routine pauses guiding.

During the autofocus, the dithering periodic triggers as the frame count on the camera increments and it tries to run a dither. It spots that PHD isn't guiding and tries to start it guiding, but ends up running out of time during the wait for settling.

A quick workaround for you would be a 'GUIDING DITHER EVERY STOP' after the 'END STOP AT' for the meridian check - that will ensure that dithering is disabled during the flip/focus.

I need to look at a number of changes that have been revealed by the complexity of this situation

* Dithering should check the number of frames captured by 'capture still frames' steps, not the number captured by the camera so it does not trigger during focus/framing/etc. In fact it should probably only trigger while a 'capture still frames' step is active

* Dithering should silently do nothing if a guiding pause is active

* Restoring guiding should allow more time for PHD2 to recover guiding

* When there is a problem in the sequencer, the log should show a 'stack trace' of the different levels of gosubs/blocks/etc that are currently active to help debug what is going on.

cheers,

Robin

[giraud]

Thanks Robin,

I have inserted the "Stop Periodic Dithering" where you recommended. Will let you know in case I experience this issue again (as a periodic dithering won't happen at every meridina flip...).

Cheers.

Eric.

[admin]

Hi Eric,

I have also implemented the changes I outlined above, which should help ensure that dithering does not try to happen during refocus or at other times when it is not appropriate - will be in next week's update.

cheers,

Robin