3. IRAF/STSDAS Tasks Used in This Script
IRAF and STSDAS Tasks Used in this Script:
Other Commonly Used IRAF and STSDAS Tasks for Working with WFPC2 Data:

Other Useful Stuff:

Some general information:
- readnoise = 5 (for single exposure)
- gain = 7 (or 14 in rare cases)
- 1 count ~ 7 electrons (if gain=7)
~ 3.6x10-18 ergs-cm2s-1 in V.
~ 22.5 V magnitude in a 1-second F555W exposure.
- 1 pixel = 0.04554 arcsecs (platescale at the center of the PC chip)
- 1 pixel = 0.09961 arcsecs (platescale at the center of the WF chips)