9.6 First Exposure Overhead Adjustment


To increase observing efficiency, a special feature of the COS instrument commanding allows a portion of the instrumental overheads for the first exposure of a visit to be performed during the initial guide-star acquisition. These will usually be target-acquisition exposures. As a result, up to 340 s of instrumental overheads (Table 9.3, Table 9.4, and Table 9.5), but not observatory or acquisition overheads (Table 9.2 and Section 9.4), may be hidden. See Section 9.7 for examples.