AstrOmatic forum
Providing a correct header template - Printable Version

+- AstrOmatic forum (
+-- Forum: AstrOmatic software (/forumdisplay.php?fid=3)
+--- Forum: SWarp (/forumdisplay.php?fid=5)
+--- Thread: Providing a correct header template (/showthread.php?tid=817)

Providing a correct header template - Antares - 12-10-2012 14:01


I am trying to combine Spitzer GLIMPSE images into one big mosaic, but I have problems creating a header corresponding to my needs.

The first problem occurs when I just tell SWarp what to do. If I set CELESTIAL_TYPE to galactic and PROJECTION_TYPE to CAR (or CEA which I would prefer) then swarp simply does not provide the entire image or it only returns a blank images with all values set to 0.

Everything works when I provide the coadd header template myself. I did this by using the Montage library which can give me a simple header with the correct dimension, but only for a TAN projection. This, of course, is not a good idea for images largen than a couple of degrees but I simply do not know how to create a header template with a GLON/GLAT-CAR/CEA projection that also includes the correct dimensions.

Is there somewhere a tool out there which can create a header template for any projection based on my input FITS files?


RE: Providing a correct header template - Emmanuel Bertin - 05-14-2013 10:39


this is a very late answer, sorry for that. First of all, the current version of SWarp uses very simple heuristics to set the output grid based on the input config parameters; these heuristics often give wrong results with very large fields of view. Hence for most projects it is strongly recommended to set the output pixel grid by directly providing WCS information in a pre-defined coadd.head header template. Unfortunately I haven't yet heard of any tool that does that fully automatically.
- Emmanuel.