galaxy
Radial Velocity of Galaxy NGC7531
Description
The galaxy  data frame records the radial velocity of a spiral galaxy 
measured at 323 points in the area of sky which it covers.  All the  
measurements lie within seven slots crossing at the origin. 
The positions of the measurements given by four variables (columns). 
Arguments
| east.west | the east-west coordinate.  The origin, (0,0), is near the center of 
the galaxy, east is negative, west is positive. | 
| north.south | the north-south coordinate.  The origin, (0,0), is near the center of 
the galaxy, south is negative, north is positive. | 
| angle | degrees of counter-clockwise rotation from the horizontal of the slot 
within which the observation lies. | 
| radial.position | signed distance from origin; negative if  
east-west coordinate is negative. | 
| velocity | radial velocity measured in km/sec. | 
 
Source
Buta, R. (1987)  The Structure and Dynamics of Ringed Galaxies, III: 
Surface Photometry and Kinematics of the Ringed Nonbarred Spiral 
NGC7531.	 The Astrophysical J. Supplement Ser.  
Vol. 64, pp. 1--37. 
John M. Chambers and Trevor J. Hastie, (eds.)  Statistical Models in S,  
Wadsworth and Brooks, Pacific Grove, CA 1992, pg. 352. 
Examples
data(galaxy)
summary(galaxy)