Saving stacked images

[AMIF]

Thank you, Robin, for the explanations! I got license finally and satisfied of Live Staking images quality. I use stacked images for photometry due to my instrumental limitations. Ideally I would need following functions:
1. Capturing of some tens of images with exposures 5-8 s.
2. Automatic calibration and stacking during or after capture.
3. Automatic plate solving.
4. Saving of stacked solved image and raw frames (calibrated).

I lost a lot of time (a huge amount of time) for manual calibration and stacking with DSS and solving with nova.astrometry.net, so even Live Stacking is real revolution in my strange process. But if SC will help with p. 3-4 - it will be excellent!

Hope for your kind advises.

Mikhail

[AMIF]

WOW!!! I found sequence:

SEQUENCE
LIVE STACK FOR 20 FRAMES SAVING AS FITSRawStack16Bit COUNTING Stacked FRAMES
END SEQUENCE

Hope, it helps!
Recommend, please, sequence for plate solving, if possble. I do not believe, that solving will work for my pure 30x20 min fields, but I hope...

[admin]

Hi,

there are a couple of sequencer steps you can use for plate solving:

'Plate solve a single frame, synce the mount and re-goto the target co-ordinates' is the most common one to use - it will try to do everything needed to put the target into the center of view. You would build it into a sequence something like this:

Code: Select all

SEQUENCE
    MOUNT GOTO RA=22:47:21.0,Dec=+58:07:56
    SET PLATESOLVE/FOCUS SETTINGS EXPOSURE 4
        MOUNT SOLVEANDSYNC
    END SET
END SEQUENCE

That will goto a set of target co-ordinates (replace the co-ordinates with your target of choice), then try to set up the camera with suitable settings for plate solving/focus (reduce exposure from normal long exposure imaging to ~4s and boost gain to compensate for reduced brightness). Then, with those camera settings, it will do a plate solve/sync/regoto, then return the camera to normal settings.

Hope this helps,

Robin

[AMIF]

Thank you, Robin!
I mean blind plate solving of stacked image. It will be useful to give approximate position by target name - variable star. Astap has variables database, and searching around target may be more successful than absolutely blind. I do not have any idea how to realise this proposal.

[admin]

Hi,

if you have a GOTO mount, and you have set it up via an ASCOM driver in SharpCap and connected to it, SharpCap will add FITS headers for RA/Dec to the saved FITS files - taking values from the mount readout. Other processing applications like ASTAP will read those RA/Dec position headers and should use them to speed up the plate solving of those images - this will all happen automatically when you save to FITS, even saving live stacked images to FITS.

If you save to other formats (PNG/TIFF/etc) then there is no real astronomy standard for header information, so the same sort of functionality isn't available. SharpCap will still save the information into the .CaptureSettings.txt file saved alongside the image though.

cheers,

Robin

[AMIF]

Regretfully I do not have GOTO.
I always successfully solved stacked images with nova.astrometry.net, but now I dream to make solving with SC directly after stacking. In manual "blind" solving is noted, and I hope to use this option for inserting coordinates to FITS header. Astap can not solve my images usually, but target star name from database may give hint for solver.
I hope very much on SharpCap!

[admin]

Hi,

the problem with adding the FITS headers when there is no GOTO mount is that SharpCap cannot be sure that they are accurate - it's unknown if the mount has moved since the last plate solve operation, or by how much it has moved. That's why the capturesettings file stores the information labelled as 'Most Recent Plate Solve' - not claiming that the figures are actually accurate, just providing the info.

cheers,

Robin

[AMIF]

Hi Robin, I can not understand how mount positions may affect on plate solving accuracy. Solver analyses pixels but not encoders impulses, does it?

BTW I found Push-to Assistant. I did not test it yet, but I feel it's the shortest way to the correct "blind" plate solving, just one step is needed

[admin]

Hi,

the plate solving will be just as accurate, but with no GOTO mount, SharpCap has no way of knowing if the mount has moved since the plate solving happened , so there is no way to be sure that the plate solving data is still relevant. I'm not convinced that putting the info into the FITS headers as 'definitive' would be a good idea in those circumstances.

cheers,

Robin

[AMIF]

I mean some kind of editing of ready image FITS header:
1. Live stacking with calibration of raw images.
2. Saving final stacked image.
3. Analysing and solving of the image.
4. Inserting image sky coordinates (but not mount position) to the FITS.

Now I make p. 1-2 with SC and p. 3-4 with Astrometry.net, and I will be glad very much to get solved images directly after stacking. I guess, target name or position may improve the process

However, postprocessing of whole seria may be better solution from POV of recording speed and stability. In this case other images solver may be used - but what???