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Last modified: December 2009

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

pix_fpc_to_gdp

Context: pixlib

Synopsis

Convert from the Focal Plane (FPC) to Grating Dispersion Plane (GDP) coordinate system.

Syntax

Array_Type pix_fpc_to_gdp( 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 Grating Dispersion Plane (GDP) coordinate system, using the current settings of the pixlib module. The inputs (x,y) are the position in the FPC system. The return value is a two-element array which gives the GDP 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> pix_set_detector( "HRC-S" );
slsh> gdp = pix_fpc_to_gdp( 42000, 17300 );
slsh> print( gdp );
40545.9
169.415

Using the default settings of the pixlib module for the HRC-S detector (i.e. the aimpoint is on HRC-S2), we find that the FPC location (42000, 17300) corresponds to the GDP position (40545.9, 169.415).

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_chip, pix_fpc_to_msc, pix_tdet_to_chip

Last modified: December 2009