Page 1 of 1

Graxpert fit file

Posted: 17 Jan 2024, 13:39
by Morten Lerager
Hi'
When process and save a fits in AA8 > Process in GraXpert save still in 32bit fits.
The file seems corrupt both in AA8 and Siril. ( Can't use DDP correct )

The header from Graxpert ends with :
BG-EXTR = 'GraXpert'
CBG-1 = 4.3567798E-06
CBG-2 = 4.3567798E-06
CBG-3 = 4.3567798E-06
INTP-OPT= 'AI '
HIERARCH SMOOTHING = 0.0
HIERARCH CORR-TYPE = 'Subtraction'
AI-VER = '1.0.1 '
END

If I then load it into the program ASTAP and save it from there.
The header end looks like this :

BG-EXTR = 'GraXpert'
CBG-1 = 4.3567798E-06
CBG-2 = 4.3567798E-06
CBG-3 = 4.3567798E-06
INTP-OPT= 'AI '
HIERARCH SMOOTHING = 0.0
HIERARCH CORR-TYPE = 'Subtraction'
AI-VER = '1.0.1 '
BZERO = 0 / physical_value = BZERO + BSCALE * array_value
BSCALE = 1 / physical_value = BZERO + BSCALE * array_value
DATAMIN = 0 / Minimum data value
DATAMAX = 65535 / Maximum data value
CBLACK = 0 / Black point used for displaying image.
CWHITE = 1 / White point used for displaying the image.
END

And now the file is perfect in both AA8 & Siril.

If i stack and save the inital file within Siril it works ok.
The bottom of the header is then :

BG-EXTR = 'GraXpert'
CBG-1 = 0.002402027
CBG-2 = 0.002402027
CBG-3 = 0.002402027
INTP-OPT= 'AI '
HIERARCH SMOOTHING = 0.0
HIERARCH CORR-TYPE = 'Subtraction'
AI-VER = '1.0.1 '
HISTORY mean stacking with winsorized sigma clipping rejection (low=3.000 high=3
HISTORY .000), additive+scaling normalized input, normalized output, no image we
HISTORY ighting, unequalized RGB
HISTORY Crop (x=52, y=60, w=3989, h=2692)
END

Is there a workaround in AA8 to fix that ?
Other Astroart users having the same experience ?

The file processed in AA8 is OK
Tombaugh 5-Crop-AA8.fit :
https://drive.google.com/file/d/10mkKzl ... drive_link

After process in GraXpert it's corrupt loaded in AA8
Tombaugh 5-Crop_GraXpert.fit :
https://drive.google.com/file/d/18doHpk ... drive_link

After load and save in ASTAP it's seems perfect again.
Tombaugh 5-Crop_GraXpert-ASTAP.fit :
https://drive.google.com/file/d/1nerWrS ... drive_link

Re: Graxpert fit file

Posted: 19 Jan 2024, 15:53
by fabdev
Hello, maybe the file is saved as floating point with range 0.0 - 1.0 ?
In this case you may fix the visualization pressing F4 or clicking the Status Bar of the image.
To restore the image to the 16 bit dynamic, use: Multiply constant 65535.

Re: Graxpert fit file

Posted: 19 Jan 2024, 16:36
by Morten Lerager
Oh, thank you Fabio

The F4 didn't work. I belive the FP in status bar means it is Floating Point
After Multiply by 65535 the FP value is changed in status bar.
And now it's perfect.