Data Set Overview
  =================
  This is a tabulation of 526 determinations of asteroid pole
  orientations, covering 104 numbered asteroids, gathered from the
  literature from 1932 through 1995. It is an updated (Dec. 1995)
  version of the tabulation given in Magnusson (1989) [MAGNUSSON1989]
  in the Asteroids II book.
 
  For more information about the Uppsala Asteroid Database, of which
  this collection is a part, see Magnusson et al. 1993
  [MAGNUSSONETAL1993].  The Uppsala Asteroid database is available by
  anonymous ftp at ftp.astro.uu.se.
 
 
  Modification History
  ====================
  This data set was first introduced into PDS under the name 'pole'
  at the April 1994 asteroid datasets review.  It was updated under
  the name 'pole' at the March 1995 review.  It was then updated
  under the new name 'spin' at the March 1996 review.  An update
  consists of adding data on asteroid spin vectors which have been
  published since the last update.
 
  Note that the prefix of the above DATA_SET_ID was changed from
  'A-5' to 'EAR-A-5' effective with version 4.0 of this data set.
 
  For Version 4.1, the original labels and this catalog file
  were substantially edited to conform with present PDS and SBN
  standards and practices. These changes included:
 
    o  The long text passage included in the general description
       of the label file was extracted into a separate
       documentation file, 'spindoc.txt'. In addition, relevant
       pieces of it were used to create DESCRIPTION fields for
       individual columns in the 'spin.lbl' file and the
       present file.
 
    o  The list of numbered notes was removed from the label
       and converted to a separate file, 'spinnote.tab', with
       its own label.
 
    o  The list of data type codes was inserted into the
       first relevant column description in 'spin.lbl'.
 
    o  Column NAME fields in 'spin.lbl' were changed to shorter,
       more displayable versions.
 
    o  A typographical error in the REFERENCE_CODE column
       of 'spin.tab' records 459 and 460 was discovered and
       corrected by inserting a '+' into the code.
 
    o  The old TeX listing of the original published paper,
       'spindoc.tex', and all the related supporting files
       have been discarded. These files were not kept up to
       date with the revised data file.
 
    o  The visually distracting and programmatically
       complicating underscores used to indicate null data
       were removed from 'spin.tab'. The 'spin.lbl' file
       was changed to state that blank fields indicate
       null data.
 
    o  The text of this file was checked against the available
       documentation and revised labels and amended as needed.
 
    o  A user reported that the labels for latitude and longitude
       columns appeared to be switched, i.e., longitudes were labelled
       and latitude and conversely. This has been corrected in the
       label.
 
  Parameters
  ==========
  The data table 'spin.tab' contains an entry for each of 526 published
  determinations of asteroid spins, plus an additional synthesis entry
  for each asteroid for which such a synthesis was warranted.  Each
  entry has fields for the following parameters: asteroid catalog
  number; a code for the type of data used to make the determination;
  four solutions for the asteroid spin direction (including rejection
  flag and pole latitude and longitude); sidereal period; flag for
  shape model; axial ratios; reference code; and notes.
 
 
  Processing
  ==========
  The principal data are taken from the published literature. In some
  cases the data supplier (P. Magnusson) converted published pole
  positions into spin axis solutions for inclusion. The following
  description is from the documentation file supplied with the data
  (and contained in 'spindoc.txt') by P. Magnusson:
 
    The table contains column space for four spin vector directions
    per line. These reflect the symmetry properties of most spin
    vector determinations. Methods based on aspect dependences
    (e.g., amplitude and magnitude methods) tend to give two spin
    axis solutions for main-belt asteroid with moderate orbital
    inclination (due to the near symmetry of the observational
    geometries in the ecliptic plane).  Corresponding to each spin
    axis solution we have two opposite spin vector directions,
    which are given explicitly in the table.  Thus, whenever the
    method used does not contain information on the sense of rotation
    I interpret 'poles' as spin axis solutions and calculate the
    implicit spin vector directions.  The result is generally four
    different solutions.
 
  In addition, for asteroids with a large number of published pole
  solutions, Magnusson has created additional entries containing
  a synthesis of published results.
 
 
 
  Data
  ====
  The following files (and their labels) constitute the data set:
 
     spin.tab          Tabulation of published results
     spinref.tab       List of reference codes and citations
     spinnote.tab      List of numbered notes
     spindoc.txt       Documentation file
 
 
  Ancillary Data
  ==============
  The data set also includes a table of full references to the
  original papers in which the data were published.  The references
  file is 'spinref.tab'.  Each entry in the data table includes a
  pointer to the reference file giving the reference of the original
  paper for that entry.
 
  The 'spinnote.tab' file contains the numbered list of notes
  mentioned in the 'spin.tab' file.
 
 
  Coordinate System
  =================
  The pole positions are expressed as ecliptic latitude and longitude,
  equinox B1950.0.  Magnusson notes:
 
    The direction of the spin vectors (defined by the 'right-hand-
    rule') are given in degrees in the ecliptic system for equinox
    B1950.0.  The corresponding ecliptic coordinates for equinox
    J2000.0 can be obtained by adding 0.7 degrees to all tabulated
    longitudes, but this adjustment is far below the level of
    accuracy for most spin vector determinations.
 
 
  Media/Format
  ============
  This data set is released in the form of ASCII files which may be
  stored on disk or other magnetic medium and which may be
  distributed by ftp, email, real-time access by remote login, or by
  whatever means is most convenient.

Confidence Level Overview
  =========================
  This is a comprehensive tabulation of determinations of asteroid
  pole orientations and senses of rotation.  No weeding out of vague
  or uncertain results has been made.
 
 
  Review
  ======
  This data set underwent formal external review on March 29, 1996.
 
 
  Data Coverage and Quality
  =========================
  The data set includes data on asteroid pole directions published
  through 1995.  152 references are cited; 526 solutions are included
  in the 'spin.tab' file; 104 different asteroids are represented.
 
  Supplementary information on shape models, albedo models, and
  sidereal period is included, but this data set is not intended to
  be a comprehensive compilation of those parameters.
 
  For those records containing a synthesis of published solutions,
  Magnusson notes:
 
    The synthesis entry is estimated to have an accuracy in
    the spin vector of 10 degrees or less.  They were obtained
    by taking averages of the most recent independent results,
    with weights based on the method used and the amount and
    type of the input data.  This procedure is necessarily
    somewhat subjective and cannot replace a careful evaluation
    of the original results.
 
 
  Limitations
  ===========
  This data set is intended only to collect data reported in the
  published literature on asteroid pole directions.