Stellar photometry including saturated images: Results on M67 with WFPC2

Ronald L. Gilliland

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23 Scopus citations


The Wide Field and Planetary Camera 2 (WFPC2) on HST is providing unsurpassed imaging capabilities and supporting accurate stellar photometry over large fields of view at high angular resolution. I discuss a feature of the WFPC2 CCD systems that nominally limits the dynamic range attainable with single exposures: a 12 bit analog to digital converter that does not allow sampling of the CCD full-well depth even at the low gain (14e-/DN) setting. I demonstrate that accurate stellar photometry can be performed on stellar images that are strongly saturated. Two 40 s exposures in V and I bands on the old open cluster M67 are analyzed to demonstrate photometric capabilities with a dynamic range of over 12 mag from single exposures. New photometric results for both bright and faint objects in M67 are derived from the WFPC2 data.

Original languageEnglish (US)
Pages (from-to)L63-L66
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Nov 1 1994

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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