OSC cal align extract photometry issue

[Mark Phillips]

Hi Han
I have been doing some photometry with OSC files and come across an issue.
I want to calibrate and align my images and then extract the green channel before photometry.
I can calibrate with no demosaic, add to photometry tab and then extract green OK. That works - but the images are not then aligned.

But I cannot calibrate and align without demosaicing, there is no option for that, so when I try and extract green I get the error
"Raw red, green or blue pixel extraction is only possible for raw images."

Any way around this?

(Also a minor issue, on most tabs I can do a Ctrl-A to select all images but this does not work on the Photometry tab)
Thanks
Mark

[han.k]

Hi Mark,

The photometry tab will align the images automatically for display only. So that the images don't move too much. The photometry measurement is done on the unmodified images.

Aligning the images prior to photometry will likely be destructive for photometric accuracy because it would rotate the images for the alignment. By doing that a part of pixels values are transferred to other pixels. That could spoil the photometry but I have never tried it.

If the images are not stable in the photometry tab then please report it. But even if the display moves a little it doesn't matter because in the last version the program looks to ra, dec position and it is also self centering on stars.

Ctrl+A, t. Did you install the latest version? It works here but maybe not in Win11. It was a problem a few weeks ago. If it is still in the last version please tell me.

Han

[Mark Phillips]

Thanks Han
I didn't know alignment wasn't needed for photometry. Will try it that way now.

I just downloaded the very latest version and Ctrl-A now works on the Photometry tab, I'm on Win 11.
Mark

[han.k]

The images can wobble a little in the photometry tab. I does a simple alignment for display only. Maybe 1 pixel movement only.

[han.k]

The photometry has been rectructered. Note the options:

• Manual star selection
• Measure all annotated (selection later in AAVSO report)
• Measure all stars (selection later in AAVSO report)

[Mark Phillips]

Yes I noticed a few changes with Comparison and Check stars in there. Looks good and it all seems to work like that. The photometry looks more reasonable to me too so maybe alignment was having an affect?

Thanks for your help as always.
Mark