PDS_VERSION_ID = PDS3
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PUBLICATION_DATE = 2006-09-29
NOTE = "Description of the CALIB directory"
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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:
| | | | | |
| | | | | Optional filter number, temperature, or
| | | | | place holder value such as '999'
| | | | |
| | | | Instrument/Image mode (1 through 9) or a place
| | | | value of '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. MRIVIS for MRI)
Directory for the type of calibration file (e.g. FLAT for flat fields)
Here is an example of a complete file name, FLAT/MRIVIS_050701_2_1_1.FIT:
- FLAT Flat field
- MRIVIS MRI Instrument
- 050701 Effective date of 2005-07-01; this flat can be applied
to images acquired on 2005-07-01 UTC or later
- 2 Version 2 of the file for the specified effective date
- 1 Instrument (image) mode 1
- 1 Filter 1
- .FIT FITS file
Calibration files are grouped into subdirectories by type:
This subdirectory contains one table for the absolute calibration
constants for each instrument (image) mode. The first column
specifies the constant for converting raw data numbers to units of
radiance, W/(M**2 SR UM). The second column specifies the constant
for converting from units of radiance to units of reflectance
(i.e., I-over-F or the observed radiance over the input solar radiance).
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. Although this correction
was omitted during the calibration of the navigation images, the
tables are provided for reference.
This subdirectory contains maps that identify bad pixels for each
instrument mode. Bad pixels are set to 1. Good pixels are set to 0.
Overscan columns and rows at the edges of the CCD array are set
flagged as good (0). There is one horizontal row of warm pixels near
the top and bottom of each map. These rows are flagged as bad (1).
This subdirectory contains a bias correction map for each instrument
mode. These maps were not used to calibration navigation images
because pre-calculated correction values (see the navigation images
report on the Deep Impact documentation volume). However, these
maps are provided for reference.
This subdirectory contains maps for modeling the dark signal for each
This subdirectory contains one transmission profile table for each
This subdirectory contains flat fields for every combination of
instrument mode and filter.
This subdirectory contains a quadrant gain correction map for each
instrument mode. The values were normalized to the gain correction at
launch. All pixels within a given quadrant have the same value.
Although gains were included in the flats, these maps are provided
This subdirectory contains a map of the two-dimensional point-spread
function (PSF) for each filter.
This subdirectory contains tables that specify the amount of gain
from electronic cross talk that occurs between all possible
combinations of the four quadrants of the CCD. Although this correction
was omitted during the calibration of the navigation images, these
tables are provided for reference.
Name Last modified Size Description
Apache/2.2.15 (Scientific Linux) Server at pdssbn.astro.umd.edu Port 443
Parent Directory -
abscalvs/ 09-Oct-2006 15:19 -
adclut/ 09-Oct-2006 15:19 -
badpix/ 09-Oct-2006 13:33 -
bias/ 10-Oct-2006 10:36 -
drkmodel/ 09-Oct-2006 14:18 -
filters/ 06-Jun-2007 12:42 -
flat/ 09-Oct-2006 18:08 -
gain/ 09-Oct-2006 18:38 -
psf/ 09-Oct-2006 15:22 -
xtalk/ 10-Oct-2006 10:26 -
calinfo.txt 06-Jun-2007 10:32 9.9K