Multi-panel sequence vs. auto-focus/guiding

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opestovsky
Posts: 9
Joined: Mon Mar 22, 2021 11:25 pm

Multi-panel sequence vs. auto-focus/guiding

Post by opestovsky »

I am trying to create a multi-panel sequence for a mosaic, so I can repeat this sequence on multiple nights without changing anything. In this particular case, it's a 4-panel sequence for the Veil nebula.
The plan is to:
move mount to panel coordinates,
plate-solve and recenter,
auto-focus,
enable guiding and dithering, take 15x4min subs, stop guiding.
Then repeat for each panel.

So I set the sequence to perform "MOUNT GOTO", "MOUNT SOLVEANDSYNC", "AUTOFOCUS", "GUIDING START", "GUIDING WAIT", "CAPTURE 15 FRAMES", "GUIDING STOP" step for each panel.
Does that sound right?

How does "GUIDING START" step work?
Does it connect the guide camera, start looping exposures, auto select guide stars and start guiding in PHD2?
What does "GUIDING STOP" step do?

Here's the actual sequence. Could you please check it for any obvious errors?
Thanks.

Code: Select all

SEQUENCE
    DELAY 1
    STILL MODE
    SET COLOUR SPACE TO RAW16
    SET OUTPUT FORMAT TO "FITS files (*.fits)"
    GUIDING CONNECT ABORT False
    FOCUSER CONNECT
	
    TARGETNAME "Veil P1"
    MOUNT GOTO "20 47 34, 31 20 48"
    PRESERVE CAMERA SETTINGS
	    SET GAIN TO 550
        SET EXPOSURE TO 10
        MOUNT SOLVEANDSYNC
        SET EXPOSURE TO 2		
        AUTOFOCUS OFFSET -75 TO 75 STEP COUNT 15 BACKLASH 0
    END PRESERVE
	
    #Capture 15 Light frames (using exposure 240s, gain 105)
    GUIDING START
    GUIDING WAIT
    PRESERVE CAMERA SETTINGS
        SET EXPOSURE TO 240
        SET GAIN TO 105
        SET OFFSET TO 20
        FRAMETYPE Light
        GUIDING DITHER EVERY 240
        CAPTURE 15 FRAMES REQUIREGUIDING True
        GUIDING DITHER EVERY STOP
    END PRESERVE
    GUIDING STOP
	
    TARGETNAME "Veil P2"
    MOUNT GOTO "20 55 37, 31 20 48"
    PRESERVE CAMERA SETTINGS
	    SET GAIN TO 550
        SET EXPOSURE TO 10
        MOUNT SOLVEANDSYNC
        SET EXPOSURE TO 2		
        AUTOFOCUS OFFSET -75 TO 75 STEP COUNT 15 BACKLASH 0
    END PRESERVE

    #Capture 15 Light frames (using exposure 240s, gain 105)
    GUIDING START
    GUIDING WAIT
    PRESERVE CAMERA SETTINGS
        SET EXPOSURE TO 240
        SET GAIN TO 105
        SET OFFSET TO 20
        FRAMETYPE Light
        GUIDING DITHER EVERY 240
        CAPTURE 15 FRAMES REQUIREGUIDING True
        GUIDING DITHER EVERY STOP
    END PRESERVE
    GUIDING STOP

    TARGETNAME "Veil P3"
    MOUNT GOTO "20 47 32, 29 38 1"
    PRESERVE CAMERA SETTINGS
	    SET GAIN TO 550
        SET EXPOSURE TO 10
        MOUNT SOLVEANDSYNC
        SET EXPOSURE TO 2		
        AUTOFOCUS OFFSET -75 TO 75 STEP COUNT 15 BACKLASH 0
    END PRESERVE

    #Capture 15 Light frames (using exposure 240s, gain 105)
    GUIDING START
    GUIDING WAIT
    PRESERVE CAMERA SETTINGS
        SET EXPOSURE TO 240
        SET GAIN TO 105
        SET OFFSET TO 20
        FRAMETYPE Light
        GUIDING DITHER EVERY 240
        CAPTURE 15 FRAMES REQUIREGUIDING True
        GUIDING DITHER EVERY STOP
    END PRESERVE
    GUIDING STOP

    TARGETNAME "Veil P4"
    MOUNT GOTO "20 55 26, 29 38 1"
    PRESERVE CAMERA SETTINGS
	    SET GAIN TO 550
        SET EXPOSURE TO 10
        MOUNT SOLVEANDSYNC
        SET EXPOSURE TO 2		
        AUTOFOCUS OFFSET -75 TO 75 STEP COUNT 15 BACKLASH 0
    END PRESERVE

    #Capture 15 Light frames (using exposure 240s, gain 105)
    GUIDING START
    GUIDING WAIT
    PRESERVE CAMERA SETTINGS
        SET EXPOSURE TO 240
        SET GAIN TO 105
        SET OFFSET TO 20
        FRAMETYPE Light
        GUIDING DITHER EVERY 240
        CAPTURE 15 FRAMES REQUIREGUIDING True
        GUIDING DITHER EVERY STOP
    END PRESERVE
    GUIDING STOP
	
	END SEQUENCE
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admin
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Re: Multi-panel sequence vs. auto-focus/guiding

Post by admin »

Hi,

that all looks promising - I can't see anything obviously wrong.

GUIDING START will attempt to begin guiding on your connected guiding application if it is not already guiding - see https://docs.sharpcap.co.uk/4.0/#!2!Guiding

GUIDING STOP will stop guiding. Useful during plate solve and sync/goto to prevent guiding from interfering with mount movements.

You should probably wrap any mount activity in

GUIDING STOP
... stuff that might move mount ...
GUIDING START

Robin
opestovsky
Posts: 9
Joined: Mon Mar 22, 2021 11:25 pm

Re: Multi-panel sequence vs. auto-focus/guiding

Post by opestovsky »

Thank you.

One more question.
In the live stacking options for dithering, there's a setting to reduce exposure time during dithering to avoid throwing away full multi minute subs during dithering.

How is that situation handled in the sequence?

Thanks.
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admin
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Posts: 6954
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
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Re: Multi-panel sequence vs. auto-focus/guiding

Post by admin »

Hi,

that's not necessary in the sequencer.

In Live Stacking you are running the camera like a video camera, capturing frames all the time. That is why you need to reduce the exposure while dithering to avoid throwing away long frames.

In the sequencer, you are running the camera like a still camera - only capturing frames on demand. Basically the sequencer will wait until one frame finishes, perform the dither and then start the next frame when the dither is complete.

cheers,

Robin
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