Yes, exactly Mike, we're lying about both things.

On Jan 31, 2013, at 8:46 AM, Mike Jarvis <notifications@github.com> wrote:

> In examples/demo11.py:
> 
> > +import os
> > +import math
> > +import numpy
> > +import logging
> > +import time
> > +import galsim
> > +
> > +def main(argv):
> > +    """
> > +    Make images using constant PSF and variable shear:
> > +      - The main image is 0.25 x 0.25 degrees.
> > +      - Pixel scale is 0.2 arcsec, hence the image is 4500 x 4500 pixels.
> > +      - Applied shear is from a cosmological power spectrum read in from file.
> > +      - The PSF is a real one from SDSS but, in order that the galaxy resolution not be too poor, we
> > +        tell GalSim that the pixel scale for that PSF image is 0.2" rather than 0.396".
> > +      - This also lets us include the pixel response in our PSF image already.
> We're also lying about the size of the SDSS PSF. The pixel response that is included in the PSF is a square with sides = 1 pixel. We're just lying about the pixel scale in general.
> 
> —
> Reply to this email directly or view it on GitHub.
> 
> 


-------------------------------

Rachel Mandelbaum
rmandelb@andrew.cmu.edu
http://www.andrew.cmu.edu/~rmandelb/