NINA, FITS file compatibility for char string

[Han K]

I checked the compatibility of the FITS files produced by NINA. The header keys with a char string as value start with a single quote ( ' ) at position 10. This should be position 11 according the FITS standard 4.0, chapter 4.2.1.1. See https://fits.gsfc.nasa.gov/fits_standard.html

More severe is the position of the first single quote for OBJCTRA and OBJCTDEC. They start at position 20. I have adapted ASTAP to read it but it is not standard.

OBJCTRA = '18 01 03' /
OBJCTDEC= '-12 59 59' /

[Stefan B]

Hey, thanks for pointing this out. I will fix this asap.

[Han K]

I think it is also better to add the mount position as float for compatibility with other programs. These two keys are often used:

RA = 83.82417125 / [deg] Telescope pointing RA
DEC = -5.385491085 / [deg] Telescope pointing DEC

Reading the string value of key OBJCTRA takes more effort to read. (ASTAP will read it anyhow) In most cases it is the image center, not the object position, so the key is a little strange. You could also use CRVAL1, CRVAL2 but some programs interpretate that as a solved image.

[Stefan B]

Yes the FITS keywords are all over the place for various applications. Unfortunately there is no single source of truth regarding those keywords (at least I know of none)

I can easily add RA and DEC as degrees to the keywords, as well.

[Stefan B]

#47e453a
Should fix this. The latest beta is available and should now produce complying fits headers.

[Han K]

For FITS keys, you could look at: https://fits.gsfc.nasa.gov/fits_dictionary.html But I agree there are many different equivalent keys.

[Han K]

FITS files produced by last ß0007 look good to me. Problem solved.

[Dale Ghent]

OBJCTRA and OBJCTDEC are currently misused in NINA and I have a patch to fix this in another branch of mine. I'm using the same value, but it is for RA and DEC instead - ie where the telescope is pointing, not what the target object's own RA and DEC are.