MIRSI detected first light on December 5, 2001, on the 60-inch telescope at the Mt. Lemmon Observing Facility (MLOF), operated by the University of Minnesota and Steward Observatory in Tucson, AZ. MIRSI's total field of view at MLOF 60-inch was about 7 x 5 arcmin, with a pixel scale of 1.3 arcsec/pixel. MIRSI is optimized for the IRTF's optics; the MLOF 60-inch has a smaller f ratio than the IRTF, which resulted in a diffraction-limited PSF with a FWHM of 3.4 arcsec at 10 microns. Since first light, we have corrected this optics discrepancy with an interface box which matches the MLOF beam so we can use the entire 60-inch mirror with an associated decrease in the size of the diffraction-limited PSF. At the IRTF, MIRSI will have a scale of 0.3 arcsec/pixel, with a diffraction-limited PSF FWHM of 0.8 arcsec at 10 microns. First light observations were presented in Deutsch et al. (2001, BAAS, 199, 102.10) (PDF | PS). A description of the MIRSI instrument is presented in Deutsch et al. (2002, SPIE, 4841-13) (PDF | PS).

Click here to see pictures of the MIRSI run at MLOF

Sample images obtained at the MLOF:

MIRSI mosaic image of Jupiter and satellites Ganymede, Europa, and Io at 11.6 microns, with a zoom on Jupiter at left.

Lunar surface (left), and shadows during Lunar sunset (right) at 11.6 microns. Thermal emission can be seen from lingering "hot spots" on the "night" side.