;---------------------------------------------------
;
;   IDL> fit, '6.dat'
;--------------------------------------------------

PRO fit, $
   filename       ; filename

   data = 0
   read_tf, data, filename, 8, 10 
   sz = size(data)
   nrows = sz(2)
   print, 'data[c,r] has:  col=',  strcompress(string(sz(1))), ' rows=',  strcompress(string(nrows))
   help, data

   x = data[6,*]
   y = data[3,*]
   print, 'xdata is ', x         
   print, 'ydata is ', y

   print, 'Linear fit is:'
   r = linfit( x, y ) 
   print, 'ha_rad = ', r[0], ' + ', r[1], ' * ape_cnt'
   print, r[0], format='(F30.20)'
   print, r[1], format='(F30.20)'

   ; print
   print, 'f(x):'
   print, r[0] + (x*r[1])

   ;  2.06e5 is DR2AS
   print, 'f(x)-y: (in arcseconds)'
   print, ((r[0] + (x*r[1])) - y ) * 2.0626480624709635515647335733077861319665970087963e5
END