4.4  Start-Up and Shut-Down Procedures

Sets of basic data for determining the absolute calibration of the detectors were obtained at the beginning and end of each MIPS instrument campaign.  Various types of well-studied astronomical sources are observed for this purpose (see section 4.1.2).  These observations did not need to be taken more frequently because of the stability of the stimulator output over time, and the exhaustive use of stimulator flashes built-in to all MIPS observing templates.  To keep the observatory observation efficiency at a maximum, ''unnecessary'' calibration data acquisition was avoided.

 

Because there is contamination on the pick-off mirror that feeds MIPS (see section 7.1.1), each campaign included sets of scan-mirror-position-dependent flat fields for the 24 μm array.

Start-up Sequence

· If not already on for IRS, switch on the Combined Electronics and other MIPS electronics requiring specific turn-on commanding.

· After the required warm-up time (0.5 hour), proceed with routine calibration measurements.

· Obtain Ge:Ga detector bias calibration observations

· Slew to MIPS ''dark sky'' region.

· Thermal anneal all detector arrays.

· Acquire dark current data frames for all arrays.

· Slew to MIPS ''flat sky'' and acquire flat field frames to provide average uniform illumination.

· Acquire flat field projector and stimulator data for the flat field matrix.

· Slew to Observatory cross-calibration flux standard(s) for 24 micron.  Observe using the Photometry AOT.

· Slew to MIPS 24 micron flux standard(s) (if different from above) and observe using the Photometry AOT.

· Slew to MIPS 70 micron flux standard(s) and observe using the Photometry AOT.

· Slew to MIPS SED flux standards(s) and observe using the SED AOT; also obtain an illumination correction.

· If not a MIPS-warm campaign, slew to MIPS 160 micron flux standard(s) and observe using the Photometry AOT.

· Proceed with science observations as planned for the instrument campaign.

Shut-down Sequence

· End science observations at the scheduled time.

· Slew to MIPS ''dark sky'' region.

· Thermal anneal all detector arrays.

· Acquire dark current data frames for all arrays.

· Slew to Observatory cross calibration flux standard(s) for 24 micron.  Observe using the Photometry AOT.

· Slew to MIPS 24 micron flux standard(s) and observe using the Photometry AOT.

· Slew to MIPS 70 micron flux standard(s) and observe using the Photometry AOT.

· Slew to MIPS SED flux standards(s) and observe using the SED AOT; also obtain an illumination correction.

· If not a MIPS-warm campaign, slew to MIPS 160 micron flux standard(s) and observe using the Photometry AOT.

· Obtain Ge:Ga detector bias calibration observations.

· If not required by IRS, switch off the Combined Electronics and other MIPS electronics requiring specific turn-off commanding.

 

 

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