meridian flip questions from beginer

[cyrille.de.brebisson]

Hello,

I am just starting in sequencer use.

I am testing a sequence that will shoot 6, 1:30h targets (320 times 15s * 6).
However, depending on start time, I have no clue when meridian flips will occur, nor when dawn will arrive.

1:
Is there a way to enclose a "CAPTURE 320 FRAMES" statement like :
if meridian reached while CAPTURE 320 FRAMES
then
begin
flip
plate solve and resync
continue
end

2: is it possible to enclose my whole sequence into construct like:
while not dawn
do
my sequence
end
MOUNT PARK

3: final question on meridian flip.
How do you handle/cause/force a meridian flip on the ascom mount as there is no "ascom flip" command?

Thanks and happy new year!

Cyrille

[admin]

Hi Cyrille,

the idea for that sort of situation was to use the block 'Run the contained steps when the mount is within <X> minutes of the meridian' - put one of those at the top of your sequence and inside it should go all the steps that actually perform the meridian flip (more on that later). SharpCap checks periodically to see if the conditions to run that block are satisfied, and will run it when they are satisfied. The checks occur between normal blocks and also between frames when capturing still frames.

So, you would need to set up the number of minutes from the meridian to be longer than your typical exposure to ensure it won't creep past the meridian between checks.

What do you put inside the block? Well for starters the 'Meridian Flip the Mount (experimental)' step is worth trying - that tries to get the mount to the same target from the other side of the pier, but unfortunately the way to do that is dependent on your exact mount (the behaviour in ASCOM drivers around the meridian is highly variable). It may help to put a delay in before the attempt to flip to allow the mount to actually reach the meridian. After the flip attempt, a 'Goto mount target co-ordinates' (these should be set by a previous GOTO) and a plate solve/resync should ensure the mount is back at the right place before imaging continues.

Of course, this is probably relatively rarely used, so it's possible you might encounter bugs or gremlins when trying this out - please do report back and I will do my best to fix them. Probably best to test on a single throwaway target that is just 10 or 15 minutes short of the meridian while you are getting this set up and tweaked - you can watch the whole thing, spot anything not working quite right, adjust and retry on another target 10 minutes away from the meridian.

For stopping at dawn and parking, use

'Stop running these steps when <Astronomical Event> happens or has already happened' - probably for astronomical dawn - put your whole sequence inside this.

'Steps to run before the sequence finishes' - put this at the top with the park step and anything else you want to run when the sequence is done

cheers,

Robin