uk.ac.starlink.ast

Class GrismMap

java.lang.Object

uk.ac.starlink.ast.AstObject

uk.ac.starlink.ast.Mapping

uk.ac.starlink.ast.GrismMap

public class GrismMap
extends Mapping

Java interface to the AST GrismMap class - transform 1-dimensional coordinates using a grism dispersion equation. A GrismMap is a specialised form of Mapping which transforms 1-dimensional coordinates using the spectral dispersion equation described in FITS-WCS paper III "Representation of spectral coordinates in FITS". This describes the dispersion produced by gratings, prisms and grisms.

When initially created, the forward transformation of a GrismMap transforms input "grism parameter" values into output wavelength values. The "grism parameter" is a dimensionless value which is linearly related to position on the detector. It is defined in FITS-WCS paper III as "the offset on the detector from the point of intersection of the camera axis, measured in units of the effective local length". The units in which wavelength values are expected or returned is determined by the values supplied for the GrismWaveR, GrismNRP and GrismG attribute: whatever units are used for these attributes will also be used for the wavelength values.

Licence

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public Licence as published by the Free Software Foundation; either version 2 of the Licence, or (at your option) any later version.

This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public Licence for more details.

You should have received a copy of the GNU General Public Licence along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street,Fifth Floor, Boston, MA 02110-1301, USA

See Also:

AST GrismMap

Nested Class Summary

Nested classes/interfaces inherited from class uk.ac.starlink.ast.Mapping

Mapping.Interpolator, Mapping.Spreader

Field Summary

Fields inherited from class uk.ac.starlink.ast.Mapping

LINEAR_INTERPOLATOR, LINEAR_SPREADER, NEAREST_INTERPOLATOR, NEAREST_SPREADER

Fields inherited from class uk.ac.starlink.ast.AstObject

AST__BAD, AST__TUNULL, pointer

Constructor Summary

Constructors

Constructor and Description
GrismMap() Create a GrismMap.

Method Summary

Modifier and Type	Method and Description
double	getGrismAlpha() Get the angle of incidence of the incoming light on the grating surface.
double	getGrismEps() Get The angle between the normal and the dispersion plane.
double	getGrismG() Get the grating ruling density.
int	getGrismM() Get the interference order.
double	getGrismNR() Get the refractive index at the reference wavelength.
double	getGrismNRP() Get the rate of change of refractive index with wavelength.
double	getGrismTheta() Get angle between normal to detector plane and reference ray.
double	getGrismWaveR() Get the reference wavelength.
void	setGrismAlpha(double grismAlpha) Set the angle of incidence of the incoming light on the grating surface.
void	setGrismEps(double grismEps) Set The angle between the normal and the dispersion plane.
void	setGrismG(double grismG) Set the grating ruling density.
void	setGrismM(int grismM) Set the interference order.
void	setGrismNR(double grismNR) Set the refractive index at the reference wavelength.
void	setGrismNRP(double grismNRP) Set the rate of change of refractive index with wavelength.
void	setGrismTheta(double grismTheta) Set angle between normal to detector plane and reference ray.
void	setGrismWaveR(double grismWaveR) Set the reference wavelength.

Methods inherited from class uk.ac.starlink.ast.Mapping

decompose, getInvert, getNin, getNout, getReport, getTranForward, getTranInverse, invert, linearApprox, mapBox, mapSplit, rate, rebin, rebinD, rebinF, rebinI, resample, resampleB, resampleD, resampleF, resampleI, resampleL, resampleS, setInvert, setReport, simplify, tran1, tran2, tranGrid, tranN, tranP

Methods inherited from class uk.ac.starlink.ast.AstObject

annul, clear, copy, delete, equals, finalize, getAstConstantI, getB, getC, getD, getF, getI, getID, getIdent, getL, getNobject, getObjSize, getRefCount, hashCode, isThreaded, reportVersions, sameObject, set, setB, setC, setD, setF, setI, setID, setIdent, setL, show, test, tune

Methods inherited from class java.lang.Object

clone, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GrismMap

public GrismMap()

Create a GrismMap.

Throws:

AstException - if an error occurred in the AST library

Method Detail

getGrismAlpha

public double getGrismAlpha()

Get the angle of incidence of the incoming light on the grating surface. This attribute holds the angle between the incoming light and the normal to the grating surface, in radians. The default value is 0.

Returns:

this object's GrismAlpha attribute

setGrismAlpha

public void setGrismAlpha(double grismAlpha)

Set the angle of incidence of the incoming light on the grating surface. This attribute holds the angle between the incoming light and the normal to the grating surface, in radians. The default value is 0.

Parameters:

grismAlpha - the GrismAlpha attribute of this object

getGrismEps

public double getGrismEps()

Get The angle between the normal and the dispersion plane. This attribute holds the angle (in radians) between the normal to the grating or exit prism face, and the dispersion plane. The dispersion plane is the plane spanned by the incoming and outgoing ray. The default value is 0.0.

Returns:

this object's GrismEps attribute

setGrismEps

public void setGrismEps(double grismEps)

Set The angle between the normal and the dispersion plane. This attribute holds the angle (in radians) between the normal to the grating or exit prism face, and the dispersion plane. The dispersion plane is the plane spanned by the incoming and outgoing ray. The default value is 0.0.

Parameters:

grismEps - the GrismEps attribute of this object

getGrismG

public double getGrismG()

Get the grating ruling density. This attribute holds the number of grating rulings per unit length. The unit of length used should be consistent with the units used for attributes GrismWaveR and GrismNRP. The default value is 0.0. (the appropriate value for a pure prism disperser with no grating).

Returns:

this object's GrismG attribute

setGrismG

public void setGrismG(double grismG)

Set the grating ruling density. This attribute holds the number of grating rulings per unit length. The unit of length used should be consistent with the units used for attributes GrismWaveR and GrismNRP. The default value is 0.0. (the appropriate value for a pure prism disperser with no grating).

Parameters:

grismG - the GrismG attribute of this object

getGrismM

public int getGrismM()

Get the interference order. This attribute holds the interference order being considered. The default value is 0.

Returns:

this object's GrismM attribute

setGrismM

public void setGrismM(int grismM)

Set the interference order. This attribute holds the interference order being considered. The default value is 0.

Parameters:

grismM - the GrismM attribute of this object

getGrismNR

public double getGrismNR()

Get the refractive index at the reference wavelength. This attribute holds refractive index of the grism material at the reference wavelength (given by attribute GrismWaveR). The default value is 1.0.

Returns:

this object's GrismNR attribute

setGrismNR

public void setGrismNR(double grismNR)

Set the refractive index at the reference wavelength. This attribute holds refractive index of the grism material at the reference wavelength (given by attribute GrismWaveR). The default value is 1.0.

Parameters:

grismNR - the GrismNR attribute of this object

getGrismNRP

public double getGrismNRP()

Get the rate of change of refractive index with wavelength. This attribute holds the rate of change of the refractive index of the grism material with respect to wavelength at the reference wavelength (given by attribute GrismWaveR). The default value is 0.0 (the appropriate value for a pure grating disperser with no prism). The units of this attribute should be consistent with those of attributes GrismWaveR and GrismG.

Returns:

this object's GrismNRP attribute

setGrismNRP

public void setGrismNRP(double grismNRP)

Set the rate of change of refractive index with wavelength. This attribute holds the rate of change of the refractive index of the grism material with respect to wavelength at the reference wavelength (given by attribute GrismWaveR). The default value is 0.0 (the appropriate value for a pure grating disperser with no prism). The units of this attribute should be consistent with those of attributes GrismWaveR and GrismG.

Parameters:

grismNRP - the GrismNRP attribute of this object

getGrismTheta

public double getGrismTheta()

Get angle between normal to detector plane and reference ray. This attribute gives the angle of incidence of light of the reference wavelength (given by attribute GrismWaveR) onto the detector. Specifically, it holds the angle (in radians) between the normal to the detector plane and an incident ray at the reference wavelength. The default value is 0.0.

Returns:

this object's GrismTheta attribute

setGrismTheta

public void setGrismTheta(double grismTheta)

Set angle between normal to detector plane and reference ray. This attribute gives the angle of incidence of light of the reference wavelength (given by attribute GrismWaveR) onto the detector. Specifically, it holds the angle (in radians) between the normal to the detector plane and an incident ray at the reference wavelength. The default value is 0.0.

Parameters:

grismTheta - the GrismTheta attribute of this object

getGrismWaveR

public double getGrismWaveR()

Get the reference wavelength. This attribute holds reference wavelength. The default value is 5000 (Angstrom). The units of this attribute should be consistent with those of attributes GrismNRP and GrismG.

Returns:

this object's GrismWaveR attribute

setGrismWaveR

public void setGrismWaveR(double grismWaveR)

Set the reference wavelength. This attribute holds reference wavelength. The default value is 5000 (Angstrom). The units of this attribute should be consistent with those of attributes GrismNRP and GrismG.

Parameters:

grismWaveR - the GrismWaveR attribute of this object