Data Set Information
DATA_SET_NAME IHW COMET HALLEY ASTROMETRIC DATA, V2.0
DATA_SET_ID IHW-C-ASTR-2-EDR-HALLEY-V2.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The Astrometry Net of the International Halley Watch (IHW) compiled astrometric observations of comet 1P/Halley from observations made by professional astronomers from ground-based observatories all over the world. The data set comprises 6475 astrometric observations over the period 16 Oct 1982 through 9 Jan 1989, in addition to 158 observations from the 1835 apparition and 1696 observations from the 1910 apparition. The data from previous apparitions was re-reduced using modern star catalogs. The data were edited by the Astrometry Net Discipline Specialists: D.K. Yeomans, R.M. West, R.S. Harrington and B.G. Marsden. The results of the original version of the modern data have been consolidated into single tables for each month of observations in this revised data set. For the previous apparitions, the single table for each apparition has been reformatted slightly to use the same formats as the modern data. 1986 Apparition : Observations were contributed by 430 observers working at 148 observatories around the world. The complete list of observers and observatories is included in ''The Comet Halley Archive Summary Volume'' (JPL D-400-450, 1991). These observations played an essential role in supporting the various flight projects dispatched to 1P/Halley, allowing for rapid updates of ephemerides and orbit determinations before, during and after encounter. Observers submitted their data to the orbit determination center at the Jet Propulsion Laboratory (JPL). The orbit determination center added the ephemeris time (ET) corresponding to the reported UTC and the observatory coordinates, as well as applying small corrections for elliptical aberration. FITS headers were added to the resulting records before delivery. The original FITS files were prepared and submitted to the IHW Lead Center at JPL by R.N. Wimberly. The version 1.0 archive was prepared under the original version of the PDS standards by E. Grayzeck, D.A. Klinglesmith III, and M.B. Niedner, Jr. 1835 and 1910 Apparitions : S.F. Roeser (Astronomisches Rechen-Institut, Heidelberg) and T.A. Morley re-reduced the visual observations available from the earlier apparitions using modern star catalogs. The revised data were gathered into a single table for each apparition, in a format similar to the data tape format used for the individual observations submitted to the Astrometry Net. Modification History : These data were originally part of the IHW 'Mixed Data' archives on CD volumes HAL_0019-0023. In their original form they consisted of files in a prototype FITS format (never adopted as part of the standard) which provided a simple FITS header above a set of ASCII records. The ASCII records were in the format of the 80-byte card images fed into the JPL ephemeris software. They included observed and corrected coordinates for the comet, error estimates, the location of the observatory, quality indicators, and comments from the observers. Personnel at the Small Bodies Node (SBN) at the University of Maryland have performed extensive reformatting of the original data. This editing includes: o FITS headers have been dropped. o All information from the FITS headers and ephemeris records have been combined into a single record for each observation in an ASCII table. o Right ascension and declination have been converted to decimal degrees (from sexigesimal notation), but left in the B1950.0 system. o Observatory latitude and longitude have been converted from sexigesimal notation to decimal degrees. o Comments from the ephemeris records have been included, unedited, as a text field in the new table records. o The observation records have been gathered into tables by the month of observation. o All reported errata have been corrected. The data from previous apparitions where in simple FITS ASCII tables. PDS personnel converted the FITS tables into flat ASCII, and reformatted the data so that individual field formats matched those used in the monthly tables for the modern data.
DATA_SET_RELEASE_DATE 2006-05-01T00:00:00.000Z
START_TIME 1835-08-21T12:05:57.000Z
STOP_TIME 1989-01-09T06:41:00.000Z
MISSION_NAME INTERNATIONAL HALLEY WATCH
MISSION_START_DATE 1980-09-01T12:00:00.000Z
MISSION_STOP_DATE 1992-09-30T12:00:00.000Z
TARGET_NAME 1P/HALLEY 1 (1682 Q1)
TARGET_TYPE COMET
INSTRUMENT_HOST_ID ASTR
INSTRUMENT_NAME IHW ASTROMETRY NETWORK
INSTRUMENT_ID ASTR
INSTRUMENT_TYPE OPTICAL TELESCOPE
NODE_NAME Small Bodies
ARCHIVE_STATUS IN_LIEN_RESOLUTION
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : Each observation in this archive was specifically chosen for inclusion by the Astrometry Net Discipline Specialists. Note that there are flag fields in the data record to give some additional indication of quality for each record, and also that details on the ancient observations are frequently scant.
CITATION_DESCRIPTION Yeomans, D.K., R.M. West, R.S. Harrington and B.G. Marsden, IHW COMET HALLEY ASTROMETRIC DATA, V2.0, IHW-C-ASTR-2-EDR-HALLEY-V2.0, NASA Planetary Data System, 2006.
ABSTRACT_TEXT The Astrometry Net of the International Halley Watch (IHW) compiled astrometric observations of comet 1P/Halley from observations made by professional astronomers from ground-based observatories all over the world. The data set comprises 6475 astrometric observations over the period 16 Oct 1982 through 9 Jan 1989, in addition to 158 observations from the 1835 apparition and 1696 observations from the 1910 apparition. The data from previous apparitions was re-reduced using modern star catalogs.
PRODUCER_FULL_NAME ANNE RAUGH
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