Wide Field Camera 3 Instrument Handbook for Cycle 19 - Space ...

28 Chapter 4: Designing a Phase I WFC3 Proposal
This total time is expressed as the (integer) number of HST orbits required to
obtain the observations.
4.2.5 Any Special Calibration Observations?
Most observers will not need to worry about special calibration observations. As a
result of ground based and SMOV testing, WFC3 is fairly well-characterized as
described in this Handbook and in more detail in WFC3 Instrument Science Reports.
Instrument characterization and calibration will be maintained and improved as part of
the ongoing calibration program conducted by STScI (Appendix E).
The main reasons an observer would need to consider special observations are
situations where a program requires greater precision than is provided through the
standard calibration program. These additional observations must be justified in your
Phase I proposal submission, and the orbits required to carry out the special
observations must be included in the overall orbit allocation requested. Proposers are
advised to discuss their need for special observations with the helpdesk.
4.2.6 What is the Total Orbit Request?
Having determined the content of the science and supporting observations
necessary to achieve your scientific objectives, you must finally determine the total
amount of HST time to carry out those activities by including the appropriate amount
of time for spacecraft and instrument overheads.
Detailed procedures for determining the total amount of time to request in your
Phase I proposal are presented in Chapter 10.