Editing Palomar Observatory (section)

===POSS-II===
{{Redirect|Second Palomar Observatory Sky Survey|POSS I|Palomar Sky Survey}}

The '''Second Palomar Observatory Sky Survey''' ('''POSS II''', sometimes '''Second Palomar Sky Survey''') was performed in the 1980s and 1990s and made use of better, faster films and an upgraded telescope. The Oschin Schmidt was upgraded with an achromatic corrector and provisions for autoguiding. Images were recorded in three wavelengths: blue (IIIaJ. 480&nbsp;nm), red (IIIaF, 650&nbsp;nm), and near-infrared (IVN, 850&nbsp;nm) plates.  Observers on POSS II included C. Brewer, D. Griffiths, W. McKinley, [[J. Dave Mendenhall]], K. Rykoski, [[Jeffrey L. Phinney]], and [[Jean Mueller]] (who discovered over 100 supernovae by comparing the POSS I and POSS II plates). Mueller also discovered several comets and minor planets during the course of POSS II, and the bright Comet Wilson 1986 was discovered by then-graduate-student C. Wilson early in the survey.<ref>Caltech: [http://www.astro.caltech.edu/~wws/poss2.html The Second Palomar Observatory Sky Survey (POSS II)] {{webarchive|url=https://web.archive.org/web/20090516193335/http://www.astro.caltech.edu/~wws/poss2.html |date=2009-05-16 }}</ref>

Until the completion of the Two Micron All Sky Survey ([[2MASS]]), POSS II was the most extensive wide-field sky survey. When completed, the [[Sloan Digital Sky Survey]] will surpass POSS I and POSS II in depth, although the POSS covers almost 2.5 times more area on the sky.

POSS II also exists in digitized form (that is, the photographic plates were scanned) as part of the [[Digitized Sky Survey]] (DSS).<ref>NASA/Space Telescope Science Institute (STScI).: [http://archive.stsci.edu/dss/ <u>M</u>ultimission <u>A</u>rchive at <u>ST</u>ScI (MAST)]</ref>