Wide Field Camera 3
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Posted by Alex Storrs on June 21, 1999 at 15:12:05:


There are a variety of specialized studies that can uniquely be done from HST and with WFC3 in
particular. The strawman filter set should allow most of these, but I'd like to suggest a few more:

1. The F1042M filter has been very useful for defining the width of the 1 micron silicate feature,
when used in connection with the F953N and other filters shortward of the feature. While the IR 
arm of WFC3 may well be more sensitive than the CCD in this region, there may be some time 
constraints on shifting from one to the other.  For a time variable object (say, a rotating planet)
the time lost may prevent a good comparison between filters. Also, wouldn't it be good to be able
to directly compare the performance of the two sides of WFC3?

2. In looking at the long wavelength end of the mineral reflectivity spectrum, there are areas
around 1.25 microns and 1.05 microns which would best be defined by medium band filters (say,
0.1 microns wide) and the intervening inflections at 1.125 microns and 1.400 microns could be
investigated with medium- or narrowband filters at those wavelengths. This set would allow the
refinement of the orthopyroxene/clinopyroxene and feldspar content of the surfaces studied.

3. Lacking an LRF, a grism would be very useful on small sources. There has not been a whole
lot about the NICMOS grism in the news primarily because the software to reduce the data has
only recently (like last week) become available. A grism will necessarily give you coverage across
telluric absorptions, which has already been discussed (see Eisenhardt's posting) as a place of
strength for WFC3.