From: Frank Masci <fmasci@ipac.caltech.edu>
Subject: Re: PSFs
Date: April 9, 2014 at 1:02:49 PM PDT
To: Tim Conrow <tim@ipac.caltech.edu>, Roc Cutri <roc@ipac.caltech.edu>, Carl Grillmair <carl@ipac.caltech.edu>, Howard McCallon <astrocat1@gmail.com>, John Fowler <jwf@ipac.caltech.edu>, Sherry Wheelock <slw@ipac.caltech.edu>

Results are in. The goal was to explore the impact of artificial core-masking on wpro photometry, even when sources are really unsaturated.

Six sources were hand-picked from a single frameset and their cores masked by different amounts to imitate saturation. Three sources already had saturated cores and these were simply expanded. The other three (unsaturated) sources were close to the saturation-threshold (dashed lines below) and were masked using a 2-pixel radius.

Conclusions:
* There’s a weak tendency for *already saturated* sources to become fainter as more of their core is masked, although we’re hurting in statistics here.
* There are no significant differences if the cores of *unsaturated* sources are artificially masked. What is this telling us?

Regards, Frank