[AstroPy] Aperture photometry

Ian Crossfield ianc at ucla.edu
Thu Apr 14 14:16:15 EDT 2011


In general, PyRAF is probably your best bet for Python-drive photometry: 
http://www.stsci.edu/resources/software_hardware/pyraf .  This software 
has a long legacy and plenty of users; the learning curve is steep, but 
worth it in the long haul.

If you need to avoid IRAF for some reason, I have some homebrew aperture 
photometry routines on my website; e.g.: 

The documentation isn't terrific, but the calling syntax is:

import phot
observation = phot.aperphot(image,  pos=[x0,y0],  dap=[dap_targ,  dap_skyinner,  dap_skyouter])

image -- can be the filename of a FITS file, or a numpy array
pos -- x,y pixel coordinates of the target
dap -- _diameters_ of apertures for photometry

Then, e.g., "observation.phot" will give you the photometric measurement 
and "observation.bg" will give you the background level.

But try PyRAF; you'll ultimately be glad you did.


Ian Crossfield
UCLA Astronomy
KH 3-145J

On 4/14/11 10:18 AM, Sergio Pascual wrote:
> Hi
> Let's say I have an image as a  numpy array and I want to obtain the
> summed values of the array inside an ellipse inside the image. In
> other words, I wanto to make aperture photometry. Do you know of any
> python astronomy package that implements this. It's a fairly basic
> think, but I haven't found anything.
> Regards

More information about the AstroPy mailing list