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Calibration

In addition to science observations, it is generally necessary to observe a comparison object for each TEXES spectral setting to allow removal of atmospheric absorption features and to correct residual flat-fielding errors. In some cases the comparison object can also provide flux calibration information, although flux calibration is necessarily uncertain due to TEXES' narrow slit.

Due to molecular features in their spectra, K and M stars do not make good comparison objects.

Documents

A description of TEXES and its use is found in the paper Lacy, J., et al., PASP, vol. 114, 153, (2002).

Summary of the August 2003 commissioning run

22 August 2003

Summary:

This run was almost fully weathered out, and very little has been done at night. We had the equivalent of 3 nights of open dome, all of which was with either very bad seeing (full distribution from 0.5 to 4", with very little time under 1.5) and/or thick cirrus. We had some opportunities to test the dither sequences with GMOS, which now work successfully for sequences without the use of the GMOS OIWFS.

Summary of the April/May 2003 commissioning runs

01 July 2003

Summary:

After a 3 months rework at HIA and at Gemini (December-February 2002), Altair was back on the sky for 2 successful commissioning runs in April and May. The integration with the telescope, TCS and sequexec is basically completed. The system is now robust and has a high level of automation. Altair now achieves 55 to 85 milliarcsec images for seeing below 0.9 arcsec.

Summary of the November/December 2002 commissioning runs

29 January 2003, updated 3 March 2003

Summary:

Altair arrived at Gemini on October 14, 2002. It went through two commissioning runs in November and December, and commissioning is proceeding well. A number of problems were encountered; most of them have been identified and fixed, or are in the process of being fixed. Strehl ratios of up to 55% with FWHM of 61mas were obtained in K band in the best conditions. The next commissioning runs are planned for April and May.