1.2 What’s New This Cycle

The following instruments will be offered in Cycle 21: two cameras on ACS (ACS/WFC and ACS/SBC), COS, FGS, STIS, and WFC3.

NICMOS is not offered for this Cycle. Please check the NICMOS Web site at: http://www.stsci.edu/hst/nicmos for current information.

•	Due to heavy scheduling in Cycle 21, Large GO programs requesting 75 orbits or more in Cycle 21 must use the shorter target visibility values from Table 6.1; this will be enforced for such programs approved for Phase II.

•	For WFC3, three new operational capabilities are available: spatial scans, charge injection for the UVIS CCDs, and greatly increased capacity in the science header buffer. See Section 4.2 for additional details.

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For COS, the new G130M central wavelength setting at 1222 Å spans the 1065 Å to 1365 Å bandpass, with resolving powers of R > 13,000 at 1135 Å and R > 10,000 at 1340 Å. This setting places the Lyman Alpha airglow line in the gap between detector segments A and B, eliminating this source of high intensity flux.