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T-ReCS Completes Imaging Commissioning and begins System Verification Science Observations

16 September 2003

Commissioning of the principal imaging mode of T-ReCS was completed during the most recent run in September and the first science data for several System Verification (SV) programs have been obtained. This milestone was the culmination of several runs in June, July and August, often fighting against poor winter weather (e.g. 15 nights out of the first 20 unusable for mid-IR observing). 

During this phase, it was demonstrated that T-ReCS and Gemini South generate high quality, diffraction-limited images throughout the 8 to 25 micron wavelength range. The point-source sensitivity is as expected based on laboratory measurements, and measurements after the telescope primary mirror was aluminized in July indicate a total system emissivity (comprising sky + telescope primary and secondary mirrors + instrument entrance window) as low as 8% at 11.7 microns. Tests of the low-resolution 10 micron spectrograph mode also demonstrated the expected sensitivity and spectral resolution.

One focus of commissioning was to enhance the performance of the telescope's chopping and nodding capabilities. After tuning these systems during the July and August runs, they operated with very high reliability during September.

Another major activity was to refine the high-level software needed to execute pre-planned observing sequences with T-ReCS. By the end of the September run, the basic functions were in routine use and the observing team was using the Observing Tool, sequence executor and On-Line Database to execute the programs defined by SV Principal Investigators.All of the imaging SV data were processed with the Gemini mid-infrared IRAF package due to be released in late 2003.

11.7 micron images of a planetary nebula observed as part of the System Verification program SV101 (left) and a typical standard star (HD 169916; right). The colour table in the latter has been stretched to show the diffraction rings.

During the September SV nights, also suffering mixed weather, three imaging mode programs were partially completed. For the next run in October the aim is to complete the imaging SV and commission low and medium resolution spectroscopy.

Last updated 2003 September 22; Tom Hayward on behalf of the Gemini andUniversity of Florida T-ReCS team