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 temperature, or place holder value
| | | | | such as '1' or '999'
| | | | |
| | | | Instrument/image mode (1 through 9)
| | | |
| | | 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. ITSVIS for ITS)
|
Directory for the type of calibration file (e.g. FLAT for flat fields)
Here is an example of a complete file name, FLAT/ITSVIS_020601_2_9_1.FIT:
- FLAT Flat field
- ITSVIS ITS Instrument
- 020601 Effective date of 2002-06-01; this flat was produced from
thermal vacuum data and can be applied to flight data
unless superseded by a flat field with a more recent
effective date for the given instrument mode
to images acquired on 2005-07-01 UTC or later.
- 2 Version 2 of the file for the specified effective date
- 9 Instrument (image) mode 9
- 1 Place holder because ITS did not have filters
- .FIT FITS file
Calibration files are grouped into subdirectories by type:
ABSCALVS
--------
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).
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. 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).
BIAS
----
This subdirectory contains a bias correction map for each instrument
mode.
DECOMPRS
--------
This subdirectory contains the four lossy lookup tables used to
decompress raw data.
DRKMODEL
--------
This subdirectory contains maps for modeling the dark signal for each
instrument mode.
FLAT
----
This subdirectory contains flat fields for each instrument mode.
GAIN
----
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.
PSF
---
This subdirectory contains a dummy point-spread function used by the
calibration pipeline when one is not available. It is a centered
delta function to prevent changes to the data.
XTALK
-----
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. There is one table
for each instrument mode. However, after this data set was delivered
to PDS for the review, it was discovered that the calibration pipeline
used in incorrect tables, containing all zeros, for instrument modes 2
through 9. The tables for these modes should have been identical to
the table for mode 1. However, this omission has a negligible effect
(less than one percent) on the calibrated data.
Apache/2.2.9 Server at pdssbn.astro.umd.edu Port 80Name Last modified Size Description
Parent Directory -
abscalvs/ 13-Jul-2006 17:16 -
adclut/ 13-Jul-2006 17:17 -
badpix/ 23-Dec-2005 15:01 -
bias/ 23-Dec-2005 15:10 -
decomprs/ 13-Jul-2006 17:18 -
drkmodel/ 30-May-2006 14:43 -
flat/ 13-Jul-2006 16:07 -
gain/ 23-Dec-2005 15:19 -
psf/ 23-Dec-2005 19:02 -
xtalk/ 24-Sep-2006 15:07 -
calinfo.txt 25-Sep-2006 10:01 9.8K