Live Stack – Online and Offline suggestions

Got an idea for something that SharpCap should do? Share it here.
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ChrisR Oz
Posts: 158
Joined: Tue Sep 28, 2021 11:03 am
Location: Melbourne

Live Stack – Online and Offline suggestions

#1

Post by ChrisR Oz »

Live Stacking is a great feature. Using it more and more, especially when I realized that I could skip some of the real-time tests (e.g. FWHM, Brightness) to save setup time and do them later carefully “offline” replaying the frames using the “Folder Camera”. Now I capture using Live Stack, saving stacked frames only, with Alignment and Guiding/dithering active (using PHD2) and enjoy the show made easy with the main histogram controls (including log X axis) coupled with the small histogram. Ideally, I should avoid the latter and leave it ‘reset’, as the “save as seen” option reduces to 8 bit PNG. But there is one problem that forces that sometimes (see below). This experience leads me to make a couple of suggestions …

Online Live Sack
I love the Live Stack histogram controls, especially with the log X axis and the real-time responsiveness to changes even with a 12M pixel camera. I capture without any colour balance in the camera controls and set the balance in the Live Stack histogram. There is just one minor issue:

Zero “black” on a log scale?
If I am tempted to nudge the black level on the main histogram, I can change it, but not set it back again. This is no doubt because the bottom of the X axis in log mode is not zero. I need to clear Log mode, drag the middle marker out of the way, set the black level marker down and then return to log mode and set the middle marker again. Or reset it all and drag the middle marker again (but reset of curves now resets the colour balance too – is this new? It really shouldn’t). It would be nice if the very bottom of the X scale was faked to transition to zero, so that the black level marker dragged all the way goes to zero.

Perhaps not Earth shattering as issues go. Because of all this, I tend to leave the Black level where the Auto set it and use the small histogram to nudge the Black level. I’d prefer not to touch the small histogram at all and “Save with adjustments” as 16 bit PNG. Still, not much work post-processing from the 16 bit PNG to fix the black level later.

Autofocus using assistant
One small change to the focussing assistants would make them much easier to use for a quick focus check before Live Stacking. When “OUT” is selected, it would be nice if it racked the focus IN by half the scan range (plus backlash) and then started the OUT scan across the previous focus position. No need to manually enter an offset focus position with cold fingers and a slow brain at 2am. I guess I could use the sequence editor to do just this, as auto focus there appears to have this behaviour. But why not here?

Offline Live Stack
Reprocessing using the “Folder Camera” permits some time spent tweaking quality filters such as FWHM and Brightness. It’s nice to watch the statistics improve and noise fade during playback. And with playback at about 1 frame per 1-2s the 60s subs go past pretty quickly. But there are one minor issue.

PNG via Folder Camera
As is common, it’s hard to recognize a RAW colour frame saved as a 16 bit mono PNG file. A checkbox declaring the mono frame as RAW colour, and perhaps a Debayer order droplist, would help greatly. Alternatively, the Colour Space droplist could include RAW16 and interpret the data as colour. Not a big issue, as I have switched to saving stills in FITS format to allow easier playback without needing to convert RAW PNG to colour FITS in PIPP.

All in all, using Live Stack is a very satisfying experience both online and offline.

Cheers, Chris.
Celestron EdgeHD 8, reducer 0.7x, Star Sense, CGX-L mount, Focuser, CPWI; Starlight Xpress AO, OAG and Filter Wheel; ZWO 294MC/294MM Pro and 174MM mini; SharpCap Pro, PHD2, Powermate 2x, Baader Neodymium, Astronomik CLS-CCD, ZWO UV/IR, Duoband filters.
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Re: Live Stack – Online and Offline suggestions

#2

Post by admin »

Hi Chris,

to attack your points in reverse order, I think that the PNG issue can already be solved using the 'Debayer Preview' control which should show in the Folder monitor camera (and ASCOM cameras for that matter) when working in with MONO source data.
Capture.JPG
Capture.JPG (28.21 KiB) Viewed 994 times
Setting this control to the correct pattern will tell SharpCap to treat the mono data as RAW for the purposes of display, live stacking, etc. It is certainly useful for the folder monitor camera and also for ASCOM colour cameras that wrongly report their sensor is monochrome (there are a good number of those out there...).

I like the idea for a 'Refocus' button that scans around the current point of focus - two in fact, one for scan in and one for scan out.

I will have to think about the black point idea - what you suggest is (hopefully) a quick/easy improvement, but there is also the idea that it might be valuable to set a *negative* black point when using darks (as with darks, the background could be close to zero). Even more interesting on a log scale :)

cheers,

Robin
ChrisR Oz
Posts: 158
Joined: Tue Sep 28, 2021 11:03 am
Location: Melbourne

Re: Live Stack – Online and Offline suggestions

#3

Post by ChrisR Oz »

Hi Robin,

Bingo! Sorry I missed the Debayer "Force RGGB". That works now like a charm using the original PNG RAW16 files.

I guess with MONO16 showing above it never occurred to me. (I believe it would be clearer/more explicit if there was a RAW16 option above, which activated the Debayer preview droplist.)

Thank you.
Cheers, Chris.
Celestron EdgeHD 8, reducer 0.7x, Star Sense, CGX-L mount, Focuser, CPWI; Starlight Xpress AO, OAG and Filter Wheel; ZWO 294MC/294MM Pro and 174MM mini; SharpCap Pro, PHD2, Powermate 2x, Baader Neodymium, Astronomik CLS-CCD, ZWO UV/IR, Duoband filters.
ChrisR Oz
Posts: 158
Joined: Tue Sep 28, 2021 11:03 am
Location: Melbourne

Re: Live Stack – Online and Offline suggestions

#4

Post by ChrisR Oz »

Hi Robin,

Interestingly, when I read PNG files from the Folder Camera, they show as "MONO16" in the Camera controls, and when they are FITS files (that truly 'know' they are colour) they shows as "RAW16", which is very logical.

But oddly, with these colour FITS files the "Debayer Preview" for the Folder Camera does not have an "ON" option, just "Off" and the "Force RGGB", etc. options. I continue to select "Force RGGB", which works.

Cheers, Chris.
Celestron EdgeHD 8, reducer 0.7x, Star Sense, CGX-L mount, Focuser, CPWI; Starlight Xpress AO, OAG and Filter Wheel; ZWO 294MC/294MM Pro and 174MM mini; SharpCap Pro, PHD2, Powermate 2x, Baader Neodymium, Astronomik CLS-CCD, ZWO UV/IR, Duoband filters.
ChrisR Oz
Posts: 158
Joined: Tue Sep 28, 2021 11:03 am
Location: Melbourne

Re: Live Stack – Online and Offline suggestions

#5

Post by ChrisR Oz »

Hi Robin,

If I can suggest a layout change? All this going from Live Stack at night (w/ Guiding/Dither on, when I remember!) and reprocessing by day (w/ Guiding/Dither off, when I remember!), it would be clearer having a few widgets reorganized.

Put the checkbox on "Monitor Guiding" under "Control" on the left, so it's more visible, like the Align, FWHM and Brightness enables. That way I'd be reminded to switch it back on at night, and off in the day!

Perhaps, to make room, we could do without the "Stacking: Sigma clipping ..." droplist there, or the "Auto Save on Clear/Close could go under the Clear and Save buttons on the left?

Cheers, Chris.
Celestron EdgeHD 8, reducer 0.7x, Star Sense, CGX-L mount, Focuser, CPWI; Starlight Xpress AO, OAG and Filter Wheel; ZWO 294MC/294MM Pro and 174MM mini; SharpCap Pro, PHD2, Powermate 2x, Baader Neodymium, Astronomik CLS-CCD, ZWO UV/IR, Duoband filters.
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Re: Live Stack – Online and Offline suggestions

#6

Post by admin »

Hi Chris,

the debayer preview thing looks like a bug - I just tested and noticed that it seems that when set to 'Off' it behaves as if 'On'! I will investigate further.

Moving the controls around is a good suggestion - particularly to bring the guiding into view, but it's also one of the trickiest things to get right so that the UI is still understandable and shows as much useful information as possible. Alongside that, I am reluctant to take things away, as when you do that you always find the people who think the most important part of the UI was the bit you just moved off to some other place!

cheers,

Robin
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