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Aspect Data at Given Times

To calculate an aspect solution for an array of given times the three input parameter THIS_UT_REF, THIS_TIME and THIS_UNIT_TIME can be specified to the getdata() methode of the aspect solution object as shown below.

IDL> data=o->getdata(this_ut_ref='2002-03-13 12:41', $
                     this_time=findgen(40), this_unit=2L^18)
IDL> help,data
DATA            STRUCT    = -> HSI_ASPECT Array[40]
IDL> help,data,/str
** Structure HSI_ASPECT, 5 tags, length=20, data length=20:
   DX              FLOAT           579.793
   DY              FLOAT          -69.4515
   PHI             FLOAT           345.195
   P_ERROR         FLOAT         0.0905938
   R_ERROR         FLOAT       0.000290888

The return value is an array of structures {hsi_aspect}. 'DX' and 'DY' are the two components of the pointing vector and 'PHI' is the roll angle, both as described above. 'P_ERROR' is the estimated error of the measured pointing and is returned in arc seconds. It includes an estimated error of the descrete pointing measurements and the induced error from the interpolation between the measured data points. The error of the roll angle is given by 'R_ERROR' and is returned in radians. Currently, it's fixed set to 1 arc minute.



Martin Fivian 2004-08-13