Telescope: NASA IRTF, Mauna Kea Instrument: SpeX (Imager) Date: 2005 July 02 UT Conditions: No clouds, humidity 15-17%, 0.4-0.7" seeing, light winds File Object UT Date UT Time Airmass Filter Itime Coadds PosAngle Slit Start Finish (sec) (deg) g20050702_0001_a.fit 9P/Tempel 1 2005-07-02 06:53:40 06:54:56 1.265 H 30.00 2 0.00 0.5x15 g20050702_0002_a.fit 9P/Tempel 1 2005-07-02 06:55:15 06:56:31 1.270 H 30.00 2 0.00 0.5x15 Optical depth at 225 GHz measured at the Caltech Submillimeter Observatory (CSO) on Mauna Kea as function of time (UT) on 2005 Jul 02. (Precipitable water vapor above the summit of Mauna Kea can be approximated by pwv (mm) ~ 20 * Tau (225 GHz), ie: for Tau (225 Ghz) ~ 0.10, pwv ~ 2 mm). UT Tau (225 GHz) 06:43 0.099 06:54 0.096 07:04 0.105