Convert from the Focal Plane (FPC) to Chip coordinate system.
(Integer_Type chip_id, Array_Type pos ) = pix_fpc_to_chip( Double_Type
x, Double_Type y )
This routine converts a position in the Focal Plane coordinate (FPC) system
to the matching position in the Chip coordinate system,
using the current settings of the pixlib module.
The FPC system corresponds to the ( DETX, DETY ) columns of
a Chandra event file.
The inputs (x,y) are the position in the FPC system.
Two values are returned: the first one is the chip ID
(the ccd_id value for ACIS and chip_id
value for HRC data) and the second (pos) is a two-element
array which gives the chip coordinates in pixels.
chips> require( "pixlib" )
chips> pix_init_pixlib
chips> ( id, chip ) = pix_fpc_to_chip( 4580, 4730 )
chips> print( id )
3
chips> print( chip )
512.423
508.93
Using the default settings of the pixlib module (i.e.
the detector is ACIS with the aimpoint on ACIS-I1), we
find that the FPC location (4580, 4730) corresponds
to the chip position (512.423, 508.93 ) on ACIS-3
(i.e. ACIS-I3).
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