Graxpert fit file

Image processing, astrometry, photometry, etc.
Post Reply
User avatar
Morten Lerager
Posts: 69
Joined: 08 Oct 2021, 14:53
Location: Denmark

Graxpert fit file

Post by Morten Lerager » 17 Jan 2024, 13:39

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
HEQ5 Pro 150PDS 60mm guide. Asiair.
Asi294mc. AA8.

fabdev
Posts: 464
Joined: 03 Dec 2018, 21:43

Re: Graxpert fit file

Post by fabdev » 19 Jan 2024, 15:53

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.

User avatar
Morten Lerager
Posts: 69
Joined: 08 Oct 2021, 14:53
Location: Denmark

Re: Graxpert fit file

Post by Morten Lerager » 19 Jan 2024, 16:36

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.
HEQ5 Pro 150PDS 60mm guide. Asiair.
Asi294mc. AA8.

Post Reply