PDS_VERSION_ID = PDS3 RECORD_TYPE = "STREAM" OBJECT = TEXT PUBLICATION_DATE = 2005-12-31 NOTE = "Description of the CALIB directory" END_OBJECT = TEXT END CALIB Directory Contents This file describes the contents of the calibration directory. The Deep Impact calibration pipeline used the files in this directory to reduce raw data. The files were the result of the analysis of ground-based, thermal- vacuum and in-flight data for the instrument. For more information about these files, the analysis, and the calibration pipeline, see the 'Deep Impact Instrument Calibration' paper included on the Deep Impact documentation volume, DIDOC_0001. The calibration data were provided as FITS image files or ASCII tables. The following file naming convention was used: CCCCC/IIIIII-YYMMDD-V-M-FFF.{FIT,TAB} | | | | | | | | | | | Optional filter number, temperature, or | | | | | place holder such as '0' or '999' | | | | | | | | | Instrument/Image mode (1 through 7) or a place | | | | holder such as '0' to indicate all modes | | | | | | | File version (1, 2, etc.) | | | | | Date from which file is valid. This is not the date the file | | was created. A value of '020601' indicates the file was | | created from thermal-vacuum data. A value of '000101' was | | used a place holder. It provides no useful information | | but was required to keep the pipeline running. | | | Instrument designation (e.g. HRIIR for HRII) | Directory for the type of calibration file (e.g. FLAT) Here is an example of a complete file name, FLAT/HRIIR_050112_1_7_0.FIT: - FLAT Flat field - HRIIR HRII Instrument - 050112 Effective date of 2005-07-01 (launch); this flat can be applied to images acquired on 2005-01-12 UTC or later - 1 Version 1 of the file file for the specified effective date - 7 Instrument (image) mode 7 - 0 Placeholder (not a filter or temperature) - .FIT FITS file Calibration files are grouped into subdirectories by type: ABSCALIR -------- This subdirectory contains one table of the absolute calibration constants for each instrument (image) mode. The first column specifies the wavelength for the reading. The second column specifies the conversion factor for areas not under the anti-saturation filter. The last column contains the conversion factors for areas under the anti-saturation filter. Two identical files, one with a place holder of '000' and another with '999' were created for the pipeline to allow existing processes to correctly execute. ADCLUT ------ This subdirectory contains a lookup table for the correcting for uneven bit weighting caused by the analog-to-digital conversion. The single table applies to all instrument modes. As of this archive, the corrections had not been derived. Therefore, the input pixel values are the same as the output values to prevent the automated calibration pipeline from changing the data. BADPIX ------ This subdirectory contains maps that identify bad pixels for each instrument mode. These are master maps where a pixel is flagged bad it was determined to be bad in each of the four in-flight science calibrations. Bad pixels are set to a value of 1. Also, the reference rows and columns around the edges of the array are set to 1. Good pixels are set to 0. BIAS ---- This subdirectory contains a dummy bias correction map for each instrument mode. All bias maps are set to zero to prevent the automated calibration pipeline from changing data. DARK ---- This subdirectory contains dark frames for specific IR exposures. The exposure ID to which this dark frame can be applied is specified in the file name. These darks were created by averaging the frames within the specified exposure ID that were not on the target (i.e., background frames). DECOMPRS -------- This subdirectory contains the four lossy lookup tables used to decompress raw data. DRKMODEL -------- This subdirectory contains master dark frames for each instrument mode. FLAT ---- This subdirectory contains dummy flat fields for each instrument mode. All flat fields are set to one to prevent the automated calibration pipeline from changing data. GAIN ---- This subdirectory contains a dummy gain correction map for each instrument mode. All gain maps are set to one to prevent the automated calibration pipeline from changing data. LINDN ----- This subdirectory contains mode-specific maps of the four coefficients used in a polynomial to linearize the raw data numbers. Mode 5 must use the mode 1 file. Modes 6 and 7 must use the mode 4 file. PSF --- This subdirectory contains a dummy point-spread function used by the calibration pipeline when one is not available. It is simply a centered delta function to prevent any changes to the data. SPECMAP ------- This subdirectory contains temperature-dependent, pixel-by-pixel, spectral registration maps for each instrument mode. The first dimension provides the wavelength; the second provides the spectral resolution (delta wavelength). The temperature string in the file names refers to the temperature of the IR spectrometer for which a map is applicable. SUNSPEC ------- This subdirectory contains two tables, based on different sources, that provide the solar spectral irradiance at 1 AU for the given wavelengths XTALK ----- This subdirectory contains tables that specify the amount of gain from electronic cross talk that occurs between all possible combinations of the two quadrants of the IR array. There is one table for each instrument mode. The cross-talk is across IR quadrants is negligible, thus the table values are set to zero the automated calibrati pipeline from changing data.