Page 1 of 1

FITS Header fields data origins

Posted: 01 Oct 2019, 01:29
by Patrick
Hello,
Can someone please explain where the data for following FITS header fields originates?:

RA
DEC
OBJECTRA
OBJECTDEC

I have images where the two RA values are the same (as are the two DEC values).

Regards,
Patrick

Re: FITS Header fields data origins

Posted: 01 Oct 2019, 10:44
by fabdev
Hello, they are both the approximate center of the image. They are not standard, but widely used.
Astroart writes both to help other programs which may support only one. They are read from the telescope.
Reference:
https://heasarc.gsfc.nasa.gov/docs/fcg/common_dict.html
https://heasarc.gsfc.nasa.gov/docs/heas ... tsExt.html

Re: FITS Header fields data origins

Posted: 05 Oct 2019, 06:48
by Patrick
Thank you - very helpful.
RA and DEC used by IRAF
Regards,
Patrick