Fermi Observations for MW 581
Mission week 581 starts with a continuation of the modified sine profile from the previous week. At 01:14 UT on day of year 199 there is a 10 minute freeze observation during which an updated modified sine profile is loaded. Then, on DOY 202 at 13:20 UT there is another 10 minute freeze observation during which a second update to the profile is loaded. This profile continues until the end of the mission week. Note that positive rock angles are south, and negative angles are north.
The Fermi Gamma-ray Space Telescope was launched from Kennedy Space Center on June 11, 2008. The observatory checkout phase completed on August 11, 2008, and Fermi is now in nominal science operations. The current status (and beautiful graphics) can be found at www.nasa.gov/fermi.
The Fermi spacecraft supports two gamma-ray instruments; the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The LAT is a wide-field gamma-ray telescope (20 MeV - 300 GeV). From the start of regular observations in August 2008 until December 2013 the LAT continuously scanned the sky, providing all-sky coverage every two orbits. In December 2013 the LAT will transition to a modified observing strategy that combines pointed observations, designed to increase coverage of the Galactic center, together with sky survey observations. Details of the new observing strategy are provided here. LAT observations may also be interrupted by occasional additional pointed observations, including target of opportunity observations, and autonomous repointing of the observatory to follow GRB afterglows, and by regular passages through the South Atlantic Anomaly (a region of high particle backgrounds). The GBM is an all-sky monitor (10 keV - 25 MeV) that detects transient events such as occultations and gamma-ray bursts. GBM detections of strong GRBs can result in an autonomous repoint of the observatory to allow the LAT to obtain afterglow observations.
For the results of LAT and GBM observations, see: