File: P11TRJSSC_FMT.txt                    Version: NSSDC 11/15/2001 JFC
------------------------------------------------------------------------

Pioneer 11 Heliocentric Coordinates for 1990-1999 
from NSSDC's Satellite Situation Center (SSC)

   Data Set Coverage (yyyy-mm-dd): 1990-01-01 to 1999-12-31

   Data Set Contact: Dr. R. (Sardi) Parthasarathy, sardi@nssdca.gsfc.nasa.gov
                     Dr. John F. Cooper, jcooper@nssdca.gsfc.nasa.gov

   Data File: P11TRJSSC.asc

   Parameter format:                                       

      YY DDD  RAD.AU  SECLAT  SECLON  HELLAT  HELLON  HILLON

      YY = YEAR
      DDD= INTEGER DAY OF YEAR (1= JAN. 1)
      RAD.AU= HELIOSPHERIC RADIAL DISTANCE IN AU
      SECLAT= SOLAR ECLIPTIC LATITUDE IN DEGREES
      SECLON= SOLAR ECLIPTIC LONGITUDE IN DEGREES
      HELLAT= SOLAR HELIOGRAPHIC LATITUDE IN DEGREES
      HELLON= SOLAR HELIOGRAPHIC LONGITUDE IN DEGREES
      HILLON= SOLAR HELIOGRAPHIC INERTIAL LONGITUDE IN DEGREES WITH RESPECT TO
              ASCENDING NODE OF SOLAR EQUATOR ON THE ECLIPTIC

   Data Source:

   These data were obtained from running the program HELICOOR in the public
   directory NSSDCA::ANON_DIR:[ACTIVE.HELIO]. These data are based on 
   predicted trajectories calculated with the GTDS code by the NSSDC Satellite
   Situation Center and converted to solar ecliptic and heliographic 
   coordinates by the HELIOCOOR program. The HELICOOR code was written by 
   R. (Sardi) Parthasarathy. The code PIOTRJSSC added the HILLON longitude.

   Note that the solar ecliptic coordinates are given with respect to true
   equinox and ecliptic of date. The solar ascending node was located at
   ecliptic longitude +74.367 degrees as of 1 Jan. 1900 at 1200 UT; this
   longitude increases by 1.4 degrees/century.


Related Information and Data:

Further details on the spacecraft, experiment, data sets at NSSDC, and related
WWW sites can be found on the Pioneer 10/11 flight project page under

http://nssdc.gsfc.nasa.gov/space/

Hour averages of the interplanetary solar wind data from, and hourly
heliocentric coordinates of, Pioneer 10/11 and other interplanetary 
spacecraft may be also be accessed and plotted on-line through the COHOWeb 
service based at the same WWW site as above. Access to the Satellite Situation 
Center (SSC) service for heliocentric coordinates from Pioneer, Voyager, Ulysses, 
and other heliocentric spacecraft is also provided from this site. 

Acknowledgement:

Use of these data in publications should be accompanied at minimum by
acknowledgements of the National Space Science Data Center and the responsible
Principal Investigator defined in the experiment documentation provided here.