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Last modified: December 2006

URL: http://cxc.harvard.edu/ciao3.4/pix_chip_to_gdp.html
Hardcopy (PDF): A4 | Letter
AHELP for CIAO 3.4 pix_chip_to_gdp Context: pixlib

Synopsis

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

Syntax

Array_Type pix_chip_to_gdp( Integer_Type chip_id, Double_Type x,
Double_Type y )

Description

This routine converts a position in the Chip coordinate system to the matching position in the Grating Dispersion Plane (GDP) coordinate system, using the current settings of the pixlib module. The inputs are chip ID (the ccd_id value for ACIS and chip_id value for HRC data) and the chip location (x,y) in pixels. The return value is a two-element array which gives the GDP coordinates in pixels.

Example

chips> require( "pixlib" )
chips> pix_init_pixlib
chips> pix_set_detector( "HRC-S" )
chips> gdp = pix_chip_to_gdp( 2, 512, 512 )
chips> print( gdp )
41331.4
17286.2

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 chip position (512,512) on HRC-S2 corresponds to the location (4620, 3573) in the GDP system.

Bugs

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

Hardcopy (PDF): A4 | Letter
Last modified: December 2006



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