NICMOS Calibration

The calibration of NICMOS data can be a particularly intricate process due to the many unique data anomalies inherent in the NICMOS cameras and electronics.

When the data arrive at STScI, they pass through the OPUS pipeline which processes and calibrates them. The calibration software used by the pipeline is exactly the sames as that provided within STSDAS. The calibration reference files and tables used are taken from the Calibration Data Base System (CDBS) at STScI and are the most up-to-date versions available at the time of the observation. However, a software tool called the dark generator now exists, which generates synthetic temperature-dependant darks. A similar, color dependent, synthetic flat-making tool called the flat generator is also available. Because of this, you may wish to re-calibrate your data using synthetic darks and/or flats, based on the nature and needs of your data. Starting in Cycle 11, when NICMOS comes back on line, the dark generator will be built into the standard calibration pipeline. This will not be relevant, however, for pre-Cycle 11 data. Additionally, users may often opt to reprocess their data regardless due to other data anomalies. Yet it is important to note, that as the understanding of the NICMOS data anomalies increases, more advanced and effective calibration tools are being developed to compensate for their affects. Slowly, these software tools are making their way into the calibration pipeline. Any developments regarding NICMOS data calibration will be published in newsletters and reports as they occur, and you can stay informed by routinely checking this website for new updates. You can find more detailed information in Chapter 3 of the NICMOS Data Handbook.