1.4	Special Considerations for Cycle 20

1.4.1 Current Instrument Status

1.4.2 Ongoing Calibration

1.4.3 New Capabilities

1.4.1

Current Instrument Status

WFC3 is operating as expected on HST, with its detectors at nominal setpoints of –83°C (UVIS) and –128°C (IR). There are no significant anomalies in its performance.

1.4.2

Ongoing Calibration

At the time of this writing, cycle 18 calibration observations have been nearly completed and cycle 19 calibration observations have begun. Descriptions of the calibration plan for each cycle are given in Appendix E. Much of the analysis of the cycle 17 and 18 calibration programs has already been documented in WFC3 Instrument Science Reports published on the WFC3 Web site; documentation of the remaining analysis is on-going.

Proposers and users of WFC3 should monitor the Cycle 20 announcement Web site for the latest information:

http://www.stsci.edu/hst/proposing/docs/cycle20announce

Additional information will be released as part of WFC3 Space Telescope Analysis Newsletters (STANs) and other updates posted directly to the WFC3 Web site:

http://www.stsci.edu/hst/wfc3

Throughout this handbook, a special “Online” symbol indicates information that is especially likely to be updated on the WFC3 Web site.

1.4.3

New Capabilities

For WFC3 three new operational capabilities are available:

•	spatial scans (see Section 6.10.3, Section 7.10.4, and Section 8.1)

•	charge injection for the UVIS CCDs (see Section 5.4.11)

•	greatly increased capacity of the Science Header Buffer (sometimes the limiting factor for subarray exposures per orbit; see Section 10.3.1 and Section 10.3.2)

Information especially likely to be updated on the WFC3 Web site is indicated by this symbol.