SIMPLE  =                    T / Standard FITS format                           
BITPIX  =                    8 / Character information                          
NAXIS   =                    0 / No image data array present                    
EXTEND  =                    T / There may be standard extensions               
BLOCKED =                    T / The file may be blocked                        
ORIGIN  = 'ADC     '           / This file written at the ADC, NASA/GSFC        
DATE    = '23/09/91'           / Date file written (dd/mm/yy)                   
                                                                                
COMMENT       Preliminary Version of the Third Catalogue of Nearby Stars        
COMMENT                                                                         
COMMENT The present version of the CNS3 contains all known stars within 25      
COMMENT parsecs of the Sun.  It depends mainly on a preliminary version (Spring 
COMMENT 1989) of the new General Catalogue of Trigonometric Parallaxes (YPC)    
COMMENT prepared by Dr.  William F. van Altena (Yale University).  The catalogue
COMMENT contains every star with trigonometric parallax greater than or equal to
COMMENT 0.0390 arcsec, even though it may be evident from photometry or for     
COMMENT other reasons that the star has a larger distance.  For red dwarf stars,
COMMENT new color-magnitude calibrations for broad-band colors were carried out 
COMMENT and applied.  For white dwarfs, the recipes of McCook and Sion in ApJS, 
COMMENT 65, 603 (1987) were applied.  Stroemgren photometry was used (not yet   
COMMENT systematically) for early-type stars and for late dwarfs, the latter    
COMMENT supplied by E. H. Olsen from Copenhagen Observatory (private            
COMMENT communication).  Contrary to the CNS2 (Gliese 1969) trigonometric       
COMMENT parallaxes and photometric or spectroscopic parallaxes were not         
COMMENT combined.  The resulting parallax in the present version is always the  
COMMENT trigonometric parallax -- if the relative error of the trigonometric    
COMMENT parallax is smaller than 14 percent.  The resulting parallax is the     
COMMENT photometric or spectroscopic parallax only if no trigonometric parallax 
COMMENT is available or if the standard error of the trigonometric parallax is  
COMMENT considerably larger.                                                    
COMMENT                                                                         
COMMENT Source Catalog Reference:  Gliese, W. and Jahreiss, H. 1991,            
COMMENT  Astronomisches Rechen-Institut Heidelberg, Germany                     
COMMENT                                                                         
COMMENT A copy of the documentation should accompany any computer-readable      
COMMENT version of the catalog.  The FITS Table header(s) in this file only give
COMMENT the basic format of the catalog.  Please refer to the documentation or  
COMMENT source reference for a more detailed discussion of the data.            
                                                                                
END