Function:     irlrs_pos2wave

Purpose:      converts inscan position to wavelength.

Category:     IRAS LRS

File:         irlrs_const.c

Author:       P.R. Roelfsema

Use:          IRLRS_POS2WAVE( DETNO    ,      Input   integer
                              INSCAN   ,      Input   real( >= NDATA )
                              NDATA    ,      Input   integer
                              LAMBDA     )    Output  real( >= NDATA )

              IRLRS_POS2WAVE - returns
                    -1 DETNO is not a legal LRS detector.
                     1 OK, DETNO is short wave detector.
                     2 OK, DETNO is long wave detector.
              DETNO  - LRS detector number.
              INSCAN - array containing in-scan offset in degree w.r.t.
                       the center of the detector os defined in IRCC_MASK.
                       POSITIVE offsets are TOWARDS the bore-sight!
              NDATA  - number of elements to be converted from position
                       to wavelength.
              LAMBDA - array containing wavelengths corresponding to INSCAN.
                       If the calculation is not valid for a given INSCAN
                       the corresponding LAMBDA gets 0 returned.
              

Updates:      Nov 27, 1990: PRR, Creation date