###Pioneer 11 Geiger Tube Telescope Calibrated Data Bundle

####Pioneer 11 GTT Daily Count Rate Data Collection

    START_TIME                       = 1973-04-07T00:00:00.000
    STOP_TIME                        = 1995-01-20T23:59:59.999
    PRODUCER_FULL_NAME               = James A. Van Allen

#####References:

Principal Investigator: Prof. James A. Van Allen, University of Iowa

***

####Collection Overview

This collection contains one file of 24-hour-averaged count rates
and related parameters from the the Geiger Tube Telescope (GTT) flown
on Pioneer 11. The data were initially provided to NSSDC by the
GTT team at U. Iowa in VMS binary format on magnetic tapes. They
have been converted to ASCII format at GSFC/SPDF, with an almost
complete retention of the original sequence of words in the data
records.

The format of the ASCII data contained in this directory follows:
         Length of record =1421bytes + LF

| Item number      |   Function                          |
|------------------|-------------------------------------|
|    1 [Note 1]    |  Year of Data  72,73 ... (ERT)      |
|    2 [Note 1]    |  Day of Data             (ERT)      |
|    3 [Note 2]    |  Beginning Day Fraction  (ERT)      |
|    4             |  Ending Day Fraction     (ERT)      |
|    5             |  Spacecraft ID (10 or 11)           |
|    6 [Note 3]    |  Length of Period in Minutes        |
|    7 [Note 4]    |  Period Type                        |
|    8             |  Number of samples this interval    |
|    9-20 [Note 5] |  Effective Counts                   |
|   21-32          |  (Sum of Raw Counts)/.09375         |
|   33-44 [Note 11]|  Counting Rate Ave in Counts/sec    |
|   45-56          |  Sigma (Standard Deviation)         |
|   57-68 [Note 6] |  M     Fourier Coefficients         |
|   69-80          |  K        "         "               |
|   81-92          |  D        "         "               |
|   93-104         |  Sum of Raw Counts                  |
|  105             |  Number of Errors this Interval     |
|  106 [Note 7]    |  Day and Day Fraction since 1950.0  |
|  107             |  Radius to SC from earth in AU      |
|  108             |  Earth-Sun distance in AU           |
|  109             |  Radius to SC from the Sun in AU    |
|  110 [Note 8]    |  Celestial Longitude of Earth       |
|  111 [Note 8]    |  Celestial Longitude of SC          |
|  112 [Note 9]    |  Longitude of Solar Equator + 270   |
|  113 [Note 8]    |  Celestial Latitude of Earth        |
|  114 [Note 8]    |  Celestial Latitude of SC           |
|  115 [Note 9]    |  Heliographic Latitude of SC        |
|  116 [Note 9]    |  Heliographic Latitude of Earth     |


       Note 1:  Earth received time  (ERT) for the data.

       Note 2:  Beginning time is the time of the first data point
                found in the interval.  The Ending time is the
                time of the last data point in the interval.

       Note 3:  This number will be the number of minutes in the
                interval since these are  24-hour averages
                the number will be 1440.

       Note 4:  This is a number assigned to describe the
                accumulation period; for 24-hour averages 
                it will be 5.

       Note 5:  Items 9 through 104 represent 8 sets of values.  The
                order of the detectors are as follows: 	 

                      Position        Detector
                          1               G
                          2               A
                          3               B
                          4               G
                          5               AB
                          6               ABC
                          7               C
                          8               D
                          9               ABC
                         10               DEF
                         11               G + G
                         12               ABC + ABC

       Note 6:  The Fourier Coefficients are used in the following 
                formula.
                F(phi) = M ( 1 + K Cos ( phi - D ) )
  
       Note 7:  This time is spacecraft event time for the center
                time of the data used in the sum.

       Note 8:  The celestial latitude and longitude are measured in a
                reference system using the Sun as the reference body
                and the true ecliptic of date as the reference plane.
                This plane contains the vernal equinox and the 
                longitudes are measured eastward from the line between
                the vernal equinox and the Sun. The latitudes are
                measured from the plane. Northward being positive.

       Note 9:  Calculated quantities.
                Inclination of solar equator to ecliptic, I=7.25 degrees.
                Longitude of the ascending node of the solar equator on
                the ecliptic Omega=73 degrees+40 minutes +50.25*t seconds
                where t is the time in years reckoned from 1850.0 .
                Reference: Explanatory Supplement to the Astronomical
                Ephemeris and the American Ephemeris and Nautical
                Almanac, 1961, page 307.

       Note 10: All positional coordinates are referred to the
                equinox/ecliptic of date.

       Note 11: A graphical display interface for these count rates is at
                omniweb-gsfc-nasa

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.
Citation of NSSDC's Coordinated Heliospheric Observations (COHO) data base
would also be appreciated, so that other potential users will be made aware of
this service.