FUSE Cycle 6 News

High-Count-Rate Observations: Effective in June 2004, MDRS is the default aperture for high-count-rate observations (HISTOGRAM mode). Use of the LWRS aperture for observations in this mode will be permitted only for strongly justified scientific reasons. This new policy was implemented in order to maintain sensitivity for faint targets. See the FUSE Observers Guide sections 2.3 and 3.2.2 for details.

Expanded sky coverage: FUSE target visibility has improved markedly over the entire sky as a result of new mission planning software and observing techniques implemented in April 2004. Sky coverage at low declinations is significantly expanded, especially in the highly restricted region near 12h and 0 degrees. However, observations in this region are still difficult and the amount of observing time available each yerar is very limited. The available observing time and the number of scheduling windows required to complete an observation remain important considerations in target selection and justification. The observing time and number of observations that can be obtained at a given RA & DEC during Cycle 6 can be determined with updated visibility software available at the Proposal Planning Tools link on the GI webpage menu sidebar http://fusegi.pha.jhu.edu

Solar System Targets: Cycle 6 visibility windows for major solar system targets are listed below.

• Jupiter visibility windows
• Mars visibility windows
• Saturn visibility windows

FUV Bright Targets: New observing techniques are being developed that extend the ability to observe targets above the nominal brightness limit (1x10^-10erg cm^-2 s^-1 Å^-1. Observations of bright targets with continuum fluxes of up to ~5x10^-10erg cm^-2 s^-1 Å^-1 will be supported in Cycle 6. Techniques for higher FUV flux levels are still being tested and calibrated. Consequently, proposed observations requiring these techniques will not accepted for Cycle 6. Details regarding Cycle 6 bright target observations are available in section 1.3 of the Cycle 6 GI Program Description and Proposal Instructions and in section 3.6.2 of the FUSE Observer's Guide.