Angle to Distance Projection

 ASI optical lens projection linearity has been tested from data taken
 in the field with a point-source of light (Gillam 940119).

 For 75 degrees field of view the quadratic and linear functions are :

 zenith=0.624315*radius + 8.27516E-04*radius**2
 zenith=0.692418*radius

 ( The linear function has been examined with star positions in data
 from 26 March 1993 , RMS error is 0.5 degrees. )

 For 90 degrees field of view the quadratic and linear functions are :

 zenith=0.593740*radius + 0.001261*radius**2
 zenith=0.712613*radius

 where zenith and radius are in terms of degrees and pixels respectively.

TST / 8 JANUARY 2003