WFPC2 Instrument Science Report 93-01:
Polarizer Quad Nomenclature
by Mark Clampin
Abstract excerpted from the report:
WFPC2 contains three quad filters which were originally designed for a four-faceted WFC configuration. One of these quad filters, QPOL, contains four polarizers with relative polarization angles of 0 deg, 45 deg, 90 deg and 135 deg. Three of the QPOL filter segments will be imaged on the WFCs, while the fourth segment is recovered for WFC imaging by a partial filter wheel rotation of -33 deg, which places it in WF2 and WF3, as is shown in Figure 1. The partially rotated filter configuration has been assigned its own filter name, QPOLN33. The purpose of this ISR is assign each of the relative polarization angles to a segment of the polarizer quad-filter.
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