COS Instrument Handbook for Cycle 25 |

help@stsci.edu |

Cosmic Origins SpectrographInstrument Handbook for Cycle 25 > Chapter 2: Special Considerations for Cycle 25 > 2.5 Non-Optimal Observing Scenarios

To optimize the scientific return of COS, we recommend that all observations be performed in TIME-TAG mode, employ the default wavelength-calibration procedures (i.e., TAGFLASH=YES), and with all four FP-POS positions (See Section 5.8) of each CENWAVE setting for the FUV gratings. Observers who wish to employ non-optimal observing techniques must strongly justify their observing strategy in the “Description of Observations” section of their Phase I proposal. A modest reduction in observational overheads will not normally be a sufficient justification for adopting non-optimal observing techniques. Whenever possible, observers should use the recommended techniques, even if this requires requesting additional resources in their Phase I proposal.

Cosmic Origins SpectrographInstrument Handbook for Cycle 25 > Chapter 2: Special Considerations for Cycle 25 > 2.5 Non-Optimal Observing Scenarios