crpurcell / polyphot

Tool to perform photometry on a FITS image by drawing polygons

Tool to perform aperture-photometry on a FITS image

This python script allows the user to display a FITS-format image and perform aperture-photometry by drawing polygons. Requires some of the utility scripts in my pyutils repository (copy util_fits.py, util_phot.py, util_misc.py to this directory).

The script was originally created to measure the properties of extended HII regions detected in CORNISH, but has also been useful for measuring fluxes in infrared GLIMPSE images. Note that the code assumes units of Janskys and will divide by the area of a beam, if the correct headers are present (BMAJ, & BMIN). Details of the formulae used are given in section 5.3.3 of the CORNISH catalogue paper.

The script saves measured values to a text file named for the input FITS file, except with a '.dat' extension. Multiple measurements can be saved per image and the script will load previous polygons if present.

Usage:

./polyphot.py G061.4770+00.0891_CORNISH_5GHz.fits