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FLAMINGOS-I 2002A Image Quality Summary

13 September 2002 
(updated 4 October 2002)

Science images taken during the 20-night Flamingos-I run in June and July 2002 have been analysed to determine the delivered image quality. Analysis was conducted on approximately 1400 frames with exposure times of typically 30-60s. Point sources were identified automatically and their image size derived by fitting a Moffat profile using the gemseeing task in the Gemini IRAF package. The images typically contain 5-10 point sources with adequate signal. Data were taken through the near-infrared J (1.25um), H (1.65um), K (2.2um) and Ks (2.15um) filters; the K and Ks results were combined for this analysis. The derived Moffat FWHM were corrected to zenith pointing by sec(z)^0.6, where z is the zenith distance (equivalently, air mass^0.6). Derived FWHM with extreme values, less than 0.15 or greater than 0.7 arcsec were checked by hand.

The histogram below shows the distribution of image FWHM for the three filters. The distributions have median values of 0.44" (J), 0.49" (H) and 0.39" (K). 

As part of normal queue execution management, observations at longer wavelength (that are less affected by seeing) were emphasised during periods of poorer image quality. This accounts for the slight tail in the K filter. Very little data were obtained in the H filter. These results are quite consistent with those found in the October 2001 Flamingos run.


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Last update October 4, 2002; Phil Puxley and Gelys Trancho