###Pioneer 11 Geiger Tube Telescope Calibrated Data Bundle

####Pioneer 11 GTT 15 Minute Count Rate Data Collection

      START_TIME                     = 1973-04-06T04:11:54.071
      STOP_TIME                      = 1995-01-23T15:31:46.696
      PDS3 DATA_SET_RELEASE_DATE     = 2010-03-04
      PRODUCER_FULL_NAME             = James Alfred Van Allen

####Collection Overview

This directory contains half-year files of 15-min 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.

In the early 1990's, as part of an archiving effort coordinated
by the Pioneer Project Office and NSSDC, U.Iowa started
providing 15-min data to NSSDC, also in vmsbinary.  All these
data sets had essentially the same words in their data records,
including particle count rates for 12 single-sensor and multi-
sensor (in coincidence) modes

The format of the ASCII data contained in this directory follows:
  Length of record =1445bytes + LF

|  Item number    |      Function                  |
|-----------------|--------------------------------|
|   1             |  ASCII timecode format of start|
|                 |  time (in spacecraft event time|
|   2 [Note 1]    |  Year of Data  72,73 ...(ERT)  |
|   3 [Note 1]    |  Day of Data            (ERT)  |
|   4 [Note 2]    |  Beginning Day Fraction (ERT)  |
|   5             |  Ending Day Fraction    (ERT)  |
|   6             |  Spacecraft ID (10 or 11)      |
|   7 [Note 3]    |  Length of Period in Minutes   |
|   8 [Note 4]    |  Period Type                   |
|   9             |  Number of samples this interva|
|  10-21 [Note 5] |     Effective Counts           |
|                 |                                |
|  22-33          |     (Sum of Raw Counts)/.09375 |
|  34-45          |     Counting Rate Ave in Counts|
|  46-57          |     Sigma (Standard Deviation) |
|  58-69 [Note 6] |     M     Fourier Coefficients |
|  70-81          |     K        "         "       |
|  82-93          |     D        "         "       |
|  94-105         |  Sum of Raw Counts             |
| 106             |  Number of Errors this Interval|
| 107 [Note 7]    |  Day and Day Fraction since 195|
| 108             |  Radius to SC from earth in AU |
| 109             |  Earth-Sun distance in AU      |
| 110             |  Radius to SC from the Sun in A|
| 111 [Note 8]    |  Celestial Longitude of Earth  |
| 112 [Note 8]    |  Celestial Longitude of SC     |
| 113 [Note 9]    |  Longitude of Solar Equator + 2|
| 114 [Note 8]    |  Celestial Latitude of Earth   |
| 115 [Note 8]    |  Celestial Latitude of SC      |
| 116 [Note 9]    |  Heliographic Latitude of SC   |
| 117 [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 quarter hour averages
                 the number will be 15.

      Note 4:    This is a number assigned to describe the 
                 accumulation period; for quarter hour averages 
                 it will be 1.

      Note 5:    Items 10 through 105 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
                 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.