Data Set Overview
  =================
    This is a comprehensive tabulation of asteroid spin vector
    determinations, compiled by Agnieszka Kryszczynska and based on
    the earlier compilation by Per Magnusson.  This is the Oct. 21,
    2007 version of the compilation, containing 863 spin vector
    determinations.  Supplementary information on shape models and
    albedo variegation is also included, but only when part of a spin
    vector determination.
 
    The following files are included in the data set:
 
    data/spin.tab - A machine-readable ASCII version of the spin
    vectors compilation
    data/spinrefs.tab - A list of the references cited in spin.tab
    data/spinnotes.tab - A list of the notes to the spin.tab table
    documents/spin.pdf - An Adobe pdf version of the spin vectors
    compilation, designed to be easily readable by eye.  It contains
    the same information as spin.tab
    documents/spininfo.asc - An explanatory document about the spin
    vectors compilation
 
    For some asteroids a large number of independent solutions have
    been published.  This may be confusing for readers who are not
    interested in the spin vector determination process as such.  For
    the benefit of readers who just want reliable results for their
    own applications a 'synthesis' is included for each asteroid.
    These synthesis results are estimated by Kryszczynska to have a
    high reliability and an accuracy in the spin vector direction of
    order 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 can't replace a
    careful evaluation of the original results.
 
    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.
 
    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 are 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, 'poles' are interpreted as
    spin axis solutions and the implicit spin vector directions are
    calculated.  The result is generally four different solutions.
    Generally the two prograde solutions are placed in the two left
    columns and the two retrograde ones in the columns to the right.
    If subsequent determinations agree reasonably then corresponding
    solutions appear in the same column, making comparison easy.  The
    4-fold symmetry is not applicable to certain objects.  The
    distinction between the four groups may break down for objects in
    high inclination orbits (e.g. 2 Pallas), for objects with spin
    axes close to the ecliptic plane, and for objects whose
    lightcurves are difficult to interpret (e.g. 532 Herculina).  For
    Earth-approaching objects it often reduces to a 2-fold clustering.
    For a discussion and analysis of this data set see Kryszczynska et
    al. 2007.
 
    This compilation of asteroid spin vectors supersedes the earlier
    compilations by Per Magnusson, upon which it has been based.
 
    References
    ==========
 
    Kryszcznska, A., A. La Spina, P. Paolicchi, A.W. Harris, S.
    Breiter, and P. Pravec, New findings on asteroid spin-vector
    distributions, Icarus 192, 223-237, 2007.

Confidence Level Overview
  =========================
    Sidereal Periods
    ==========
 
    Only periods accurate enough to bridge inter-apparitional gaps and
    produce absolute rotational phases for the whole data set are
    included.  Less accurate synodic period determinations exist for
    many more objects.  As evident from the table, the agreement
    between sidereal period determinations tend to be either very good
    or very bad.  This is due to the non-uniform time-distribution of
    the observations, which tend to give many well-defined local
    chi-square minima.
 
    Ellipsoidal Models
    ===========
 
    Many pole determination methods are based on a tri-axial ellipsoid
    model with semi-axes a>=b>=c rotating about the c-axis.
    Corrections for non- geometric scattering and albedo variegation
    have often not been made.  A warning must therefore be made
    against direct identification of the model axis-ratios with the
    asteroid shape.  Note that the table is not a comprehensive list
    of asteroid shapes, but includes models obtained as by-products of
    spin vector determinations only.
 
    Albedo Variegation
    ============
 
    Albedo models are also often by-products of spin-vector
    determinations, and therefore noted in the table.  However, the
    table is not a complete collection of such models.