         the picture left Mars at time `etemit', when Mars was at a
         different state than at time `etrec'.
 
         In order to solve this problem, we could use the `<a href="sincpt_c.html">sincpt_c</a>'
         routine for both pixels, but this would be slow.  Instead, we
         will assume that the light time for each pixel is the same. We
         will call `<a href="sincpt_c.html">sincpt_c</a>' once to get the light time and surface point
         associated with the boresight. Then, we wil