Re: ztf images and aperture photometry

Posted by karenacollins on May 24, 2022; 4:56am
URL: http://astroimagej.170.s1.nabble.com/ztf-images-and-aperture-photometry-tp1918p1928.html

Hi Scott,

We expect you may have "Use RA/Dec to place apertures" enabled in the Multi-Aperture panel. When this mode is enabled, the fits header must contain information that allows AIJ to convert from X,Y coordinates to RA/Dec coordinates, and a separate set of header information for the reverse translation from RA/Dec back to X,Y coordinates. From a quick look at the headers in the example image you linked, I can see the translation parameters from X,Y to RA/Dec, but couldn't spot headers for the inverse direction.

If the above interpretation is correct, there are two options that will allow you to use the images in current versions of AIJ. (1) You can re-platesolve the images with AIJ or another tool that will update the full plate-solution in the header. (2) If there is no reason you need to place apertures by RA/Dec, simply disable the Multi-Aperture option "Use RA/Dec to place apertures" and (at least according to the sample image) multi-aperture works just fine without spending the time to re-platesolve all images.

Thanks for your investigatory work on this issue Kevin E!

Karen