WIYN 3.5m Observatory

WIYN Status - Semester 2012A Proposer Information

WHIRC Filters

14 September 2011: As part of a science initiative by Matt Bershady, we will be replacing two of the WHIRC filters late this fall. The two replacement filters, which will be permanent contributions to the WHIRC filter complement, are designed to study the gravity-sensitive CO and CN bands in cool stars as a discriminant for determining luminosity classes in both galactic star-forming regions and in nearby galaxies. The two filters will be a somewhat broader and redder narrowband CO filter, which will replace the current CO filter, and a CN narrowband filter at 1.1 microns.

The new CO filter will be centered near 2.34 microns with a bandwidth of approximately 0.1 micron and should include the 2-0, 3-1, 4-2, and 5-3 CO first overtone bands. Although the thermal background will be higher than with the current CO filter (which was rarely used), the new filter will include more of the overall CO absorption. It is also closer to the narrowband CO filters which had been used in single-channel photometric observations of late-type stars. The new CN filter, in combination with the Low-airglow and HeI filters, can discriminate between carbon-rich and oxygen-rich AGB stars by virtue of their sampling the VO and TiO band heads in the latter.

Based on the usage of the current filters, we have decided that the CN filter will replace the redshifted Paschen beta filter. Since there are only two narrowband filters in the H band, we felt that both of the [FeII] filters should be retained. In the K band, the redshifted Brackett gamma filter serves as a continuum narrowband filter for both the Brackett gamma and H2 filters, and will also provide a continuum point for the new CO filter. While this could potentially impact some future science programs, we felt that replacing the least-used filter to be the best choice. Moreover, this is not necessarily a permanent change, as the redshifted Paschen beta (or another new filter required for a specific science program) may be installed at a future date.

WIYN Dome Repairs

Repairs to the WYN dome, which suffered damage in a winter storm in January 2010, may necessitate closing the facility for some period in the 2012A semester. The current estimate is a shutdown of ~6 weeks, sometime in the March - June time period. Updated information will be posted here. Please be as flexible as possible about your observing dates when submitting an observing proposal for semester 2012A.

MiniMo Upgrade

In addition, plans are underway to upgrade the MiniMo imager. This upgrade will include new detectors, electronics, and operating system. Plans are currently underway to deploy this new imager in early 2012A, but this timeline is contingent on several things. Please submit your proposal assuming that the available imager will be MiniMo. If your proposal is awarded time, and the new imager becomes available, WIYN will contact you to help plan your observations.

Any questions can be directed to Patricia Knezek (pknezek at noao.edu).