'nuskypos' calculates the SKY position of the telescope optical axis, of the aperture stop center and of a reference pixel in the DET1 frame. This module is called by the 'nucoord' script.
The location of the optical axis in the DET2 frame is stored in the CALDB alignfile. 'nuskypos' reads this position and transforms it in the SKY frame using the attitude and teldef files provided in input trough the parameters 'attfile' and 'teldef', respectivel. The SKY position of the optical axis of the aperture stop center as a function of time is stored in the output file 'optaxisfile'.
The 'nuskypos' also calculates the DET2 and SKY coordinates of the center of the aperture stop. The location of the aperture stop center in the DET1 frame is stored in the CALDB alignfile. The task 'nuskypos' reads this position and converts the Focal Plane Bench Frame (DET1) coordinates into the Optics Bench Frame (DET2) detector coordinates using the mast aspect solution file ('mastaspectfile'). As a second step, the DET2 coordinates are transformed in SKY coordinates using the attitude and teldef files. The DET2 and SKY positions of the aperture stop center are stored in the output file 'optaxisfile'.
Moreover, 'nuskypos' calculates the SKY coordinates of a reference pixel in the DET1 frame provided in input via the parameters 'det1xref' and 'det1yref'. The task first converts the DET1 coordinates into the DET2 coordinates using the mast aspect solution file ('mastaspectfile'). As a second step, the DET2 coordinates are transformed in SKY coordinates using the attitude and teldef files. The SKY position of the detector reference pixel as a function of time is stored in the output file 'det1reffile'.
> nuskypos mastaspectfile=nu40060001001_mast.fits attfile=nu40060001001_att.fits pntra=258.3 pntdec=-23.7 alignfile=nuCalign20100101v003.fits teldef=nuA20100101v001.teldef instrument=FPMA optaxisfile=nu40060001001A_oa.fits det1reffile=nu40060001001A_det1.fits