NICMOS Instrument Handbook for Cycle 11

Calibration Plans

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The calibrations available during Cycle 11 will be based on two distinct calibration activities. First, the activity known as SMOV, which is currently scheduled to happen around the middle of Cycle 10, will provide science-enabling and initial calibrations for all NICMOS science modes. Second, the routine Cycle 11 calibration program will provide the necessary observations to achieve the goals set in Table 13.1.

In the current schedule, NICMOS is expected to be operational again during the second half of Cycle 10. A fraction of the Cycle 11 calibrations will be executed early to support a timely start of NICMOS science operations.

 

It is important to distinguish between the various goals of these calibration activities. SMOV is intended to demonstrate that the instrument is functioning as expected, based on both previous experience and expectations under NCS operations, to establish necessary operation parameters (e.g. plate scale), and to begin the calibration and scientific use of NICMOS. In many cases the complete calibration will be conducted during Cycle 11 with SMOV being used to demonstrate that the planned calibrations are in fact feasible. This approach is designed to enable the acquisition of science observations at the earliest possible date, even if the best possible calibrations do not become available until some time later. This contributes to the efficiency with which HST can be operated.

The planned NICMOS SMOV activities are listed in Table 13.2, for reference. The baseline of the SMOV plan for NICMOS consists of 20 activities, of which 12 are calibration-related. Some of these test specific components of the instrument while others characterize its performance within the HST environment. A number of proposals are aimed at testing the detector's temperature stability under NCS operations, and performance changes with temperature variations.

Table 13.2: Planned (preliminary) NICMOS SMOV Activities 

Activity Title	Demonstrates or Calibrates
NICMOS Filter Wheel Mechanism Test	Verify the mechanical operation of each filter wheel.
NICMOS FOM Operation Test	Verify the mechanical operation of the FOM.
NICMOS Flats,/Quantum Efficiency	Determine changes in debris (grot) and measure QE as a function of temperature.
NICMOS Detector Read Noise, Shading, Cosmic Ray Rates	Characterization of detector noise and dark current. Comparison and bootstrap from Cycle 7N warm-up. Re-verification of CR rate.
NICMOS Transfer Function Test	Set optimal detector DC offset voltages.
NICMOS Fine Optical Alignment	Optimal positioning of the PAM based on grid of small PAM motions.
NICMOS NIC3 Fine Optical Alignment	Optimal positioning of the PAM /FOM for NICMOS camera 3.
NICMOS Coronagraphic Focus	Determine the optimal chronographic focus position.
NICMOS Focus Monitor	Monitoring of NICMOS best focus position (stability).
NICMOS Aperture Locations	Establish the locations of the NICMOS detectors within the FGS coordinate system.
NICMOS Plate Scale	Determine plate scales, relative field rotations, and field distortions for each camera.
NICMOS Mode 2 Target Acquisition Test	Demonstrate Mode 2 (on-board) acquisitions.
NICMOS Chronographic Performance	Optical characterization of chronographic stray light rejection and PSF of the obscured star.
NICMOS Internal Flats	Demonstration of flat fielding capability and stability monitoring.
NICMOS Photometric Test	Standard star observations across NICMOS wavelength range. Updates SLTV throughput calibration.
NICMOS SAA Cosmic-Ray Persistence Test	Measurement of decay time of SAA cosmic ray events.
NICMOS Astronomical Persistence Test	Characterize the effect of severe overexposure of the NICMOS detectors.Measurements of decay time for photon persistence.
NICMOS Thermal Background	Characterization of HST generated thermal background over a broad range of situations.
NICMOS Grisms Absolute Sensitivity	Determine Grisms sensitivity. Compare with Cycle 7 performance.
NICMOS Grisms Wavelength Calibration	Derive wavelength calibrations for Grisms. Compare with Cycle 7 performance.