Astroart Forum

Hi, Astro Image J looks for WCS coordinates, so i used AA5 to find coordinates which it did, and I saved the new header. However AIj doesnt see the file has having WCS although the header appears to have those key words. If i solve the file in Astrometrica, then AIJ is happy. There is one difference i see, AA5 RA-DEC is in degress, whereas as Astrometrica is hhmmss

Is there an explanation ?

Thank Tim

Hi, the keywords "RA" and "DEC" are not WCS keywords, they are the approximate coordinates of the center of the image, usually they are written from the telescope coordinates.
Try removing them from the Astrometrica or Astroart image, nothing should not change.

The WCS coordinates are: CTYPE1 , CTYPE2 , CRVAL1 , CRVAL2 , CRPIX1 , CRPIX2 and the four CD.. keys of the matrix.

OK thanks fabdev. I understand now -
Tim