Skip to the navigation links
Last modified: December 2009

URL: http://cxc-newtest.cfa.harvard.edu/ciao4.2/pix_fpc_to_chip.html
AHELP for CIAO 4.2

pix_fpc_to_chip

Context: pixlib

Synopsis

Convert from the Focal Plane (FPC) to Chip coordinate system.

Syntax

(Integer_Type chip_id, Array_Type pos ) = pix_fpc_to_chip( Double_Type
x, Double_Type y )

Description

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.

The pixlib module is not available by default; to use it in a S-Lang program, it must be loaded using the S-Lang require() function:

  require("pixlib");

Example

slsh> require( "pixlib" );
slsh> pix_init_pixlib;
slsh> ( id, chip ) = pix_fpc_to_chip( 4580, 4730 );
slsh> print( id );
3
slsh> print( chip );
512.362
508.892

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 (512.362, 508.892) on ACIS-3 (i.e. ACIS-I3).

Bugs

See the bugs page for the pixlib library on the CIAO website for an up-to-date listing of known bugs.

See Also

modules
pixlib
pixlib
pix_chip_to_fpc, pix_chip_to_gdp, pix_chip_to_tdet, pix_fpc_to_gdp, pix_fpc_to_msc, pix_tdet_to_chip

Last modified: December 2009