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Michelle Imaging Polarimetry

22 Feb 2006

Imaging polarimetry commissioned

The imaging polarimetry mode of Michelle was commissioned in December 2005 and January 2006. Reduction and analysis of the commissioning data is still going on (special thanks to Chris Packham of the Univeristy of Florida who has been assisting us in looking at the data).

Indications from these observations are that the intrinsic instrumental polarization of Michelle is small, less than 0.2 to 0.3 percent. However it is clear that stable conditions are needed for good quality polarimetry data to be obtained.

Imaging polarimetry will be offered for science programs in 2006B and beyond. Spectral polarimetry is to be commissioned in 2007B.

Michelle Si-3 and Si-4 Filter Leaks Eliminated

During the period where Michelle was off of the telescope in the fall of 2005 (due to NIFS commissioning) blocking elements were inserted into the filter wheel in front of the Si-3 9.6um and Si-4 10.4um filters. The same blocking elements were already in place in front of the Si-1 and Si-2 filters. Observations taken on December 18, 2005, of a very "red" target did not show any sign of the leak that had previously been seen in these filters. A similar change of blocking elements was done for T-ReCS and they have also verified that the leaks are gone.

Last update Feb 22, 2006; Kevin Volk