 as for the
               input `target'.

               [1,c3] = size(ilusrc); char = class(ilusrc)

                  or

               [1,1] = size(ilusrc); cell = class(ilusrc)

      et       is the epoch, expressed as seconds past J2000 TDB,
               for which the apparent illumination angles at the
               specified surface point on the target body, as seen
               from the observing body, are to be computed.

               [1,1] = size(et); double = class(et)

      fixref   