Data Set Information
DATA_SET_NAME GEOGRAPHOS RADAR V1.1
DATA_SET_ID EAR-A-GST-3-RDR-GEOGRAPHOS-RADAR-V1.1
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : Goldstone radar observations of 1620 Geographos from August 28 through Sept. 2, 1994 yield delay-Doppler images whose linear spatial resolutions range from ~75 to ~151 meters, and 138 pairs of continuous-wave, dual-polarization (OC/SC) (opposite circular/ same circular) spectra with one-dimensional resolution of 103 m. These data are presented in Ostro, et al. (1996), Icarus 121, 46 [OSTROETAL1996], and are included in this data set. A full description of the observations and the reduction process is provided in the paper. Data : Individual images from each successful radar run are in FITS files 'ge[Nxx].fit' where N is the last digit of DOY (day of year) and xx is the run number within that day. The low-resolution images are collected in a collage image 'gelrcoll.fit', and the high- resolution images in a collage image 'gehrcoll.fit'. Multi-run sums of co- registered images from 30 degree blocks of rotational phase, for the low- and high-resolution images respectively, are in files 'gelrsum.fit' and 'gehrsum[N].fit' (N:1,3 for the three high- resolution summed images). The collages and summed images are the same as the data presented in Figures 8-11 of the paper. The scaling of the images is explained in the following excerpt from the paper: 'Data values for each image in this paper are mapped onto a 256-level gray scale. Since the noise background is not interesting, all data values below a clipping level near the noise mean are mapped to black to make the most of the gray scale's available dynamic range. Similarly, all data values above some saturation level are mapped to white, since the contrast at the very highest echo levels contains less interesting information than contrast among the more abundant dimmer pixels.' The levels chosen for clipping and saturation level for each image are recorded in the label description for that image. 138 individual continuous wave (cw) power spectra are collected in the file 'gecwall.tab', and spectra from the bandwidth extrema are in 'gecwext.tab'. These spectra are the same as those presented in Figures 2 and 7 of the paper. Ancillary Data : An index of the data with observational circumstances for each run is given in the file geindex.tab. Modification History : These data were reviewed internally as part of a general review of all Small Bodies Node holdings in April 2002. Minor modifications were made to the data labels and documentation files to bring this data set up to current SBN standards. The following changes were made: o Specific times for each image and spectrum file were retrieved from Ostro, et al. (1996) and inserted into labels and catalog files as appropriate. o The AXIS_ORDER_TYPE keyword was added to all image labels to reflect the column-major ordering of the FITS images. o The TARGET_NAME value was changed from 'GEOGRAPHOS' to the standard format '1620 GEOGRAPHOS' everywhere it occured. o DESCRIPTION fields were added to individual image files to indicate whether each image is high or low resolution. o Additional description was added to some labels to clarify the relationship between the data presented here and the corresponding plots and images in Ostro, et al. (1996) [OSTROETAL1996]. o Some file names in the 'Data' section above were discovered to be in error and were corrected. o The object type in the 'gecwall' and 'gecwext' label files was changed from SPECTRUM to TABLE, because the files do not meet the strict PDS requirements on the SPECTRUM object.
DATA_SET_RELEASE_DATE 1998-03-23T00:00:00.000Z
START_TIME 1994-08-28T07:11:00.000Z
STOP_TIME 1994-09-02T10:16:00.000Z
MISSION_NAME SUPPORT ARCHIVES
MISSION_START_DATE 2004-03-22T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME 1620 GEOGRAPHOS
GEOGRAPHOS
TARGET_TYPE ASTEROID
INSTRUMENT_HOST_ID GDSCC
INSTRUMENT_NAME GOLDSTONE DEEP SPACE NETWORK ANTENNA DSS-14
INSTRUMENT_ID DSS14
INSTRUMENT_TYPE RADAR
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Review : This data set underwent external peer review on March 23, 1998.
CITATION_DESCRIPTION TBD
ABSTRACT_TEXT Delay-Doppler images and continuous wave, dual-polarization spectra of 1620 Geographos taken during the August 1994 closest approach to Earth (0.0333AU at minimum).
PRODUCER_FULL_NAME CAROL NEESE
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