Instrument Science Report 2009-01:

Rapid Pinhole Growth in the F160BW Filter

J. Biretta and K. Verner

March 25, 2009

Abstract:

The WFPC2 Filter F160BW, also known as the Wood’s filter, was designed to transmit UV emission around 150nm and strongly block all other wavelengths. The filter has a unique construction where a thin film of sodium metal serves as the spectral element. However, sodium is a highly unstable and reactive metal, which makes the filter susceptible to changes over time. Herein we report a rapidly growing pinhole in the filter located in the field of view of the WF2 CCD. Observers requiring a high rejection of out-of-band light (i.e. red leak) should take note of this feature, and avoid the affected region in the field-of-view.

The Complete Paper (PDF 1.0 MB) is available.