Data Set Information
DATA_SET_NAME DEEP IMPACT 9P/TEMPEL CRUISE - RAW HRIV CALIB DATA V1.0
DATA_SET_ID DIF-CAL-HRIV-2-9P-CRUISE-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : This data set contains raw science calibration images acquired by the Deep Impact High Resolution Instrument Visible CCD (HRIV) during the cruise phase of the mission to comet 9P/Tempel 1. The data set does not contain images of the comet. The science calibration images are described in the 'Deep Impact In-Flight Calibration Summary' document and are also discussed in the 'Deep Impact: Anticipated Flight Data' paper by Klaasen, et al. (2005) [KLAASENETAL2005]. Calibration targets included the Moon, Jupiter, 16 Cyg A, Achernar, Beta Hyi, Canopus, Vega, HD 60753, HD 79447, M11, NGC 3114, NGC 3532, an internal calibration (stimulator) lamp, and dark frames. For a detailed discussion of how the instrument was calibrated, see 'Deep Impact Instrument Calibration' by Klaasen, et al. (2006) [KLAASENETAL2006]. A list of the images for science calibrations in the data set is provided here: Mid-Obs Exposure IDs Date DOY Minimum Maximum Mission Activity ---------- --- ------- ------- -------------------------- 2005-01-14 014 1000000 1000005 Checkout 2005-01-15 015 1000006 1010015 Checkout 2005-01-16 016 1100000 1100053 Moon/Earth Science Cal 2005-01-30 030 1500000 1500024 Lunar Science Cal 2005-02-04 035 1500000 1500024 Lunar Science Cal Rerun 2005-02-06 037 1200441 1300007 Flyby Autonav Test 2005-02-15 046 1700000 1700050 HRIV Focus Test 2005-02-21 052 1700000 1700050 HRIV Focus Test 2005-03-08 067 1700000 1700010 HRIV Focus Test 2005-03-11 070 1700000 1700010 HRIV Focus Test 2005-03-13 072 1700000 1700010 HRIV Focus Test 2005-03-15 074 1700000 1700010 HRIV Focus Test 2005-03-17 076 1700000 1700010 HRIV Focus Test 2005-03-18 077 1700000 1700010 HRIV Focus Test 2005-03-19 078 1700000 1700010 HRIV Focus Test 2005-03-21 080 2200000 2240005 HGA Jitter Test 2005-03-24 083 9000848 9001003 Encounter Validation Test 2005-04-05 095 2000000 2010047 April Science Cal 2005-04-06 096 2020000 2030026 April Science Cal 2005-04-07 097 2040000 2040041 April Science Cal 2005-04-08 098 2060000 2070026 April Science Cal 2005-04-18 108 4200011 4200017 Autonav MRI/HRI Alignment 2005-04-23 113 4200011 4200017 Autonav MRI/HRI Alignment 2005-04-27 117 1800000 1800035 HRIV Stray Light 2005-04-28 118 1800036 1800099 HRIV Stray Light Essential Reading ----------------- The following documents, located on the Deep Impact Documentation volume, DIDOC_0001, are essential for the understanding and interpretation of this data set: ANTICIPATED_FLIGHT_DATA.* : Anticipated flight data by Klaasen, et al. (2005) [KLAASENTAL2005] INFLIGHT_CALIBRATION_SUMMARY.* : Summary of in-flight calibrations CALIBRATION_DOC.* : Instrument calibration by Klaasen, et al. (2006) [KLAASENETAL2006] INSTRUMENTS_HAMPTON.* : Instrument paper by Hampton, et al. (2005) [HAMPTONETAL2005] MISSION_OVERVIEW_AHEARN.* : Mission overview by A'Hearn, et al. (2005) [AHEARNETAL2005B] SCLK_CORRELATION.* : Discussion of the discrepancy between the spacecraft clocks and UTC AIDC_FLIGHT_HRIV_MRI_ITS.* : Description of the data set and definitions of label keywords Related Data Sets ----------------- The following PDS data sets are related to this one: DIF-CAL-HRIV-2-9P-ENCOUNTER-V1.0 : Raw HRIV encounter data DIF-C-HRIV-3/4-9P-ENCOUNTER-V1.0 : Reduced HRIV encounter data DIF-CAL-HRII/HRIV-2-GROUND-TV2-V1.0 : HRIV pre-flight calib data DIF-CAL-HRII/HRIV/MRI-2-GROUND-TV4-V1.0 : HRIV pre-flight calib data DI-C-SPICE-6-V1.0 : SPICE kernels Processing : The uncompressed and compressed FITS images in this data set were created by the Deep Impact Science Data Center (SDC) at Cornell University and were assembled from raw telemetry packets sent down by the flyby spacecraft. Information from the embedded spacecraft header (the first 100 bytes of an uncompressed or 50 bytes of a compressed image) was extracted and stored in the primary FITS header. Geometric parameters were computed using the best available SPICE kernels and the results were also stored in the FITS header. If telemetry packets were missing, the corresponding pixels were flagged as missing in the quality map included as a FITS 'IMAGE' extension. The image quality map is described in the calibration pipeline section of the 'Deep Impact Instrument Calibration' paper by Klaasen, et al. (2006) [KLAASENETAL2006]. The SDC did not apply any type of correction, decompression, or deconvolution algorithm to the raw data. Applied Coherent Technology Corporation in Herndon, VA, produced the PDS data labels by extracting parameters from the FITS headers. Data : CCD Images ---------- The two-dimensional, visible CCD images in this data set are in FITS format. The primary data array contains the CCD image and is followed by an image extension that contains a pixel-by-pixel quality map. Each FITS file is accompanied by a detached PDS label. Compression ----------- This data set contains compressed and uncompressed raw FITS images, that is, data as they were received on the ground. Data compression was performed on board the spacecraft using a set of four lossy lookup tables. A compressed FITS image consisted of 14-bit values compressed and stored as a one-byte pixel. An uncompressed FITS image consisted of 14-bit pixels stored as two bytes. The COMPRESSED_IMAGE_VALUE in the data label indicates if an raw image is compressed or uncompressed. The COMPRESSOR_ID identifies the lookup table that was used to compress an image. The calibration pipeline decompressed raw images. For information about data compression, refer to 'An Overview of the Instrument Suite for the Deep Impact Mission' by Hampton, et al. (2005) [HAMPTONETAL2005] or the instrument calibration paper by Klaasen, et al. (2006) [KLAASENETAL2006]. Target Name and Description --------------------------- The TARGET_NAME keyword in the data labels was set to the intended target, 'Calibration'. The TARGET_DESC keyword provides the name of the specific calibration target, such as 'Dark'. True-Sky ''As Seen By Observer'' Display ---------------------------------------- A true-sky view is achieved by displaying the image using the standard FITS convention: the fastest-varying axis (samples) increasing to the right in the display window and the slowest- varying axis increasing to the top. This convention is also defined in the image labels: SAMPLE_DISPLAY_DIRECTION : 'RIGHT' LINE_DISPLAY_DIRECTION : 'UP' This topic is discussed in detail in the 'Quadrant Nomenclature' section of the 'Deep Impact Instrument Calibration' document. The direction to Celestial North and Ecliptic North, measured clockwise from the top of the displayed image, is provided in PDS labels by CELESTIAL_NORTH_CLOCK_ANGLE and SOLAR_NORTH_POLE_CLOCK_ANGLE, both of which assume the correct display defined by SAMPLE_DISPLAY_DIRECTION and LINE_DISPLAY_DIRECTION. File Naming Convention ---------------------- The naming convention for the data labels and FITS files is HVcccccccccc_eeeeeee_nnn.LBL or FIT where cccccccccc is the spacecraft clock count at the mid-point of the observation, eeeeeee is the exposure ID (OBSERVATION_ID in data labels). Up to 999 individual images could be commanded for one exposure ID. Therefore, nnn in the file name provides the sequentially increasing image number within an exposure ID corresponding to IMAGE_NUMBER in the data labels. For example, if two images were commanded for exposure ID 9000022, the two FITS files names would be HV0173709840_9000022_001.FIT and HV0173709840_9000022_002.FIT. Parameters : Data Units ---------- Raw image data are in units of raw data numbers. Imaging Modes and Filters ------------------------ For descriptions of the imaging modes and filters, please see the Deep Impact instrument paper by Hampton, et al. (2005) [HAMPTONETAL2005]. Most image modes had a set of bias overclock rows and columns, located around the edges of the image array. All overclock pixels were excluded from the calculation of the values for MINIMUM, MAXIMUM, MEDIAN, and STANDARD_DEVIATION in the data labels. Time-Related Keywords --------------------- All time-related keywords in the data labels, except EARTH_RECEIVED_TIME, are based on the clock on board the flyby spacecraft. EARTH_RECEIVED_TIME provides the UTC when an Earth-based observer should be able to see an event recorded by the instrument. The TIME_FROM_IMPACT_VALUE keyword in the data labels was based on the estimated impact time at the flyby spacecraft of UTC 05:44:35.821 on 4 Jul 2005. Geometry-Related Keywords ------------------------- The SDC attempted to calculate geometric parameters relating to the target only when it was within several fields of view of the instrument boresight. When these parameters could not be calculated, the corresponding keywords in the PDS data labels were set to a value of unknown (UNK). Also, geometry-related keywords for calibration targets such as Canopus were set to UNK. Geometry-related parameters in the PDS data labels are uncertain at a level of a few seconds because of a known 2-second discrepancy between the clocks on board the flyby and impactor spacecraft and between in-situ data and ground-based observations. The Deep Impact project generated self-consistent SPICE kernels, outside of NAIF, to help account for the discrepancy. The November 2005 version of these kernels was used to calculate the image times and geometric information in PDS data labels. After further analysis of the timing problem in early 2006, improved self-consistent SPICE kernels were generated by the Deep Impact project. These kernels are included in the DI SPICE data set. For more information about this discrepancy, please see the spacecraft clock correlation document included on the Deep Impact document volume. Ancillary Data : Geometric parameters included in the data labels were computed using the November 2005 version of the SPICE data. These were the best available data at the time of image creation. Since image creation, some SPICE data have been improved, and these are archived in the Deep Impact SPICE data set. Coordinate System : Earth Mean Equator and Vernal Equinox of J2000 (EME J2000) was the inertial reference system used to specify observational geometry parameters in the data labels. Geometric parameters provided in the data labels were computed at the epoch specified by MID_IMAGE_TIME, except for the target-to-sun and earth-observer-to-target parameters. Target-to-sun values were calculated for the time when the light left the sun while earth-observer-to-target were calculated for the time when the light left the target.
DATA_SET_RELEASE_DATE 2005-12-31T00:00:00.000Z
START_TIME 2005-01-14T11:53:54.322Z
STOP_TIME 2005-04-28T04:37:41.118Z
MISSION_NAME DEEP IMPACT
MISSION_START_DATE 2005-01-12T12:00:00.000Z
MISSION_STOP_DATE 2005-07-13T12:00:00.000Z
TARGET_NAME CALIBRATION
TARGET_TYPE CALIBRATION
INSTRUMENT_HOST_ID DIF
INSTRUMENT_NAME DEEP IMPACT HIGH RESOLUTION INSTRUMENT - VISIBLE CCD
INSTRUMENT_ID HRIV
INSTRUMENT_TYPE CCD CAMERA
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : As noted above, the geometry-related parameters in the PDS data labels are uncertain at a level of a few seconds because of a known 2-second discrepancy between the clocks on board the flyby and impactor spacecraft and between in-situ data and ground-based observations. For more information about this discrepancy, please see the spacecraft clock correlation document included on the Deep Impact document volume. The FITS files in this data set were reviewed internally by the Deep Impact project and were used extensively by the science team to calibrate the instruments. Review : This data set passed a PDS peer review that took place on April 5, 2006. Reviewers stated these data should be archived pending resolution of the liens produced during the review. Data Coverage and Quality : All expected data were received on the ground and are included in this data set. Horizontal striping through some images indicates missing data. The image quality map extension identifies where pixels are missing. If the second most-significant bit of a pixel in the image quality map is turned on, then data for the corresponding image pixel is missing. For more information, refer to the notes about image quality map in the PDS data label or to the 'Deep Impact Instrument Calibration' paper. Limitations : HRI Telescope Focus ------------------- Raw HRIV CCD images are blurred because the HRI telescope was out of focus. In-flight bakeouts during late February and early March 2005 reduced the defocus from about 1.0 cm to about 0.6 cm, resulting in a decrease in the width of stars from about 12 pixels to 9 pixels. For more details, please see the instrument calibration paper by Klaasen et al. (2006) [KLAASENETAL2006]. The raw HRIV images in this data set have not been deconvolved. Displaying Images ----------------- Flight software overwrote the first 50 uncompressed (or 100 compressed) pixels of first quadrant read out from the instrument with an image header. These original header pixels were included in the raw FITS images. Since the values in these pixels vary dramatically, it recommended that the values of the MINIMUM and MAXIMUM keywords in the PDS data label (or the MINPVAL and MAXPVAL in the FITS header) be used to scale an image for display because these values exclude the header bytes as well as the overclock rows and columns located around the edge of the image. The location of the header bytes in a FITS image depends on the readout order of the instrument, as discussed in the quadrant nomenclature section of the 'Deep Impact Instrument Calibration' paper.
CITATION_DESCRIPTION McLaughlin, S. A., B. Carcich, T. McCarthy, M. Desnoyer, and K.P. Klaasen, DEEP IMPACT 9P/TEMPEL CRUISE - RAW HRIV CALIB DATA V1.0, DIF-CAL-HRIV-2-9P-CRUISE-V1.0, NASA Planetary Data System, 2005.
ABSTRACT_TEXT This data set contains raw science calibration images acquired by the Deep Impact High Resolution Instrument Visible CCD during the cruise phase of the mission.
PRODUCER_FULL_NAME STEPHANIE MCLAUGHLIN
SEARCH/ACCESS DATA
  • SBN Comet Website
    		•