POLE DETERMINATIONS OF ASTEROIDS                           
                                                                                
                              Per Magnusson                                     
                                                                                
                        Astronomiska Observatoriet                              
                                 Box 515                                        
                             S-75120 Uppsala                                    
                                 Sweden                                         
                                                                                
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.  An indication of the reliability (or lack thereof)      
of the solutions may be obtained by comparing results derived from different    
sources of data (see column 2).  Discussions of the individual pole             
determination methods, including their merits and weaknesses, are given         
in the chapter "Determination of Pole Orientations and Shape Parameters of      
Asteroids" appearing in this volume.                                            
                                                                                
Note when the letter is 'R', it is followed by a comment which fills the        
following field.                                                                
                                                                                
POLE COORDINATES:                                                               
  These are given in the ecliptical reference frame of equinox 1950.            
  For symmetry reasons, two-pole solutions often result for main-belt asteroids;
  thus two sub-columns are tabulated. In order to simplify comparison between   
  results, the coordinates always refer to the pole above the orbital plane,    
  and the pole longitude is occasionally given outside the range 0-360 degrees. 
  The spin direction is indicated by proceeding the coordinates with the        
  letter "N" if they refer to the north pole (direction of spin-vector) and     
  the letter "S" if the coordinates refer to the south pole (anti-direction of  
  spin-vector). Otherwise this byte contains a '-'. The word "rejected"         
  indicates a pole solution shown to be inconsistent with observations.         
  A pole solution within parenthesis is significantly less likely than the      
  other solution.                                                               

SENSE OF ROTATION: 
  The sense of rotation is termed "Indeterminate" (I) when the spin direction   
  is known, but the accuracy of the pole coordinates is insufficient to give    
  an unambigous sense of rotation, or the pole is so close to the ecliptic      
  and/or orbital plane that forced precession is likely to cause the sense of   
  rotation to alternate on a time-scale short compared to the age of the        
  planetary system.                                                             

SIDEREAL PERIOD: 
  Given in days.  Due to the usually nonuniform time-distribution of            
  the observations, sidereal periods tend to be either very accurate or, when   
  the number of rotation cycles is wrongly determined, erroneous by hundreds    
  of times the expected uncertainty.                                            
                                                                                
MODEL:                                                                          
  Many pole determination methods are based on a triaxial ellipsoid model       
  with semiaxes a>b>c that rotate 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.  Values within parentheses are assumed   
  model parameters and not determined values.                                   
                                                                                
  An "A" in byte (71) indicates a quantitative model of albedo variegation. The 
  table is not a comprehensive list of asteroid shapes and albedo models, but   
  includes models obtained as by-products of pole determinations. This field    
  contains other comments as well.                                              
                                                                                
Acknowledgments                                                                 
                                                                                
I thank Drs. R. Taylor, D.F. Lupishko and F.P. Velichko for pointing out        
several mistakes and omissions in an earlier version of the table and           
Dr. J. Drummond, who sent unpublished results.