SCUCD

The SCUCD extension contains information on telescope movements. It is slightly different for JIGGLE (MAP and PHOTOM) and SCAN observations. For a JIGGLE observation it has the following format:

STRUCT.MORE.SCUCD  <SCUCD_ST>

   JIGL_X(64)     <_REAL>         -2.6883,-5.3457,-8.033999,-13.3797,
                                  ... 5.3457,2.6883,0,2.6883,0,2.6883,0,0
   JIGL_Y(64)     <_REAL>         1.545,3.09,1.545,1.545,3.09,4.635,6.18,
                                  ... -9.27,-7.725,-6.18,-4.635,-3.09,0
   DEC1           <_REAL>         0
   DEC2           <_REAL>         0
   LST_STRT(2,4,3,1)  <_DOUBLE>   5.6288711444511,5.630383297715,
                                  ... 5.6639924748021,5.6623806283313
   RA1            <_REAL>         0
   RA2            <_REAL>         0

and for a SCAN observation:

STRUCT.MORE.SCUCD  <SCUCD_ST>

   JIGL_X         <_REAL>         0
   JIGL_Y         <_REAL>         0
   DEC1(1,5,1,1)  <_REAL>         -17.06608,-17.04154,-17.10884,-17.07168,
                                  -17.11085
   DEC2(1,5,1,1)  <_REAL>         -17.03781,-17.09083,-17.04711,-17.11225,
                                  -17.09126
   LST_STRT(1,5,1,1)  <_DOUBLE>   5.521871430823,5.5231108938446,
                                  ... 5.5266851885263,5.5281428875176
   RA1(1,5,1,1)   <_REAL>         21.16225,21.16618,21.16226,21.1673,
                                  21.16577
   RA2(1,5,1,1)   <_REAL>         21.16466,21.16197,21.16755,21.1638,
                                  21.16747
   WPLATE         <_REAL>         0

The full description of these entries follows:

JIGL_X and JIGL_Y

These are the X and Y coordinates of the jiggle pattern in arcsecond offsets. The coordinate frame is given in the SAM_CRDS FITS keyword. They are only used for JIGGLE observations.

LST_STRT

This is the local sidereal time of the start of every switch expressed as decimal radians. It has dimensions of N_SWITCHES, N_EXPOSURES, N_INTEGRATIONS, and N_MEASUREMENTS. The current epoch of observation (Modified Julian Date) is calculated from the UTSTART and UTDATE FITS keywords in SCULIB_GET_MJD.

RA1, DEC1, RA2 and DEC2

This is the apparent RA and Dec of the start (RA1, DEC1) and end (RA2, DEC2) of the scans in radians. The dimensions are N_SWITCHES, N_EXPOSURES, N_INTEGRATIONS, and N_MEASUREMENTS. The current epoch of observation (Modified Julian Date) is calculated from the UTSTART and UTDATE FITS keywords in SCULIB_GET_MJD.

WPLATE

For polarimetry observations (POLPHOT or POLPMAP) this array contains the waveplate angle for each measurement (where a measurement is defined as a move of the waveplate). It is used by the SURFLIB_FILL_WPLATE routine.