Converts a direction into parallactic angle. More...

#include <ParAngleMachine.h>

Public Member Functions
	ParAngleMachine ()
	Create an empty machine.
	ParAngleMachine (const MDirection &in)
	Construct for the specified direction.
	ParAngleMachine (const ParAngleMachine &other)
	Copy constructor (deep copy)
ParAngleMachine &	operator= (const ParAngleMachine &other)
	Copy assignments (deep copy)
	~ParAngleMachine ()
Quantum< Vector< Double > >	operator() (const Quantum< Vector< Double > > &ep) const
	Return parallactic angles (epoch in days if given as Double)
Quantum< Vector< Double > >	operator() (const Vector< MVEpoch > &ep) const
Quantum< Vector< Double > >	operator() (const Vector< MEpoch > &ep) const
Quantum< Double >	operator() (const Quantum< Double > &ep) const
Quantum< Double >	operator() (const MVEpoch &ep) const
Quantum< Double >	operator() (const MEpoch &ep) const
Double	operator() (const Double &ep) const
Vector< Double >	operator() (const Vector< Double > &ep) const
void	set (const MDirection &in)
	Will have a group of set methods (in direction; reference time; a frame; a reference time valid period.
void	set (const MeasFrame &frame)
void	setInterval (const Double ttime)
	Set the test interval (in days) over which to use simple formula.
Private Member Functions
Double	posAngle (const Quantum< Double > &ep) const
	Get position angle (Epoch is supposed to be in days if Double)
Vector< Double >	posAngle (const Quantum< Vector< Double > > &ep) const
Double	posAngle (const Double &ep) const
Vector< Double >	posAngle (const Vector< Double > &ep) const
void	init ()
	Initialise machinery.
void	initConv () const
	Initialise conversion.
Double	calcAngle (const Double ep) const
	Calculate position angle.
Private Attributes
MDirection *	indir_p
	Input direction.
MDirection::Convert *	convdir_p
	Conversion engine.
MeasFrame *	frame_p
	Measure frame.
MVDirection	zenith_p
	Converted zenith.
MVDirection	mvdir_p
	Intermediate conversion result.
Double	lastep_p
	Time of last full solution (in days)
Double	defintvl_p
	Default time interval over which to do simple solution (days)
Double	intvl_p
	Time interval over which to do simple solution (days)
Double	UTfactor_p
	Calculation cache.
Double	longoff_p
Double	longdiff_p
Double	slat1_p
Double	clat1_p
Double	slat2_p
Double	clat2_p

Detailed Description

Converts a direction into parallactic angle.

Intended use:

Public interface

Review Status

Reviewed By:: Mark Wieringa
Date Reviewed:: 2001/10/06
Test programs:: tParAngleMachine

Prerequisite

MDirection class

Etymology

From Parallactic Angle and machinery

Synopsis

The construction of a ParAngleMachine class object creates a machine that can create parallactic angles from a series of time epochs given.

The machinery needs an input MDirection to specify the input coordinates reference direction and coordinate system. The parallactic (vertical) angle will be calculated as the angle between the vertical in the local coordinate system (Az, El) through the given direction and the pole of the J2000 coordinate system.
Tip: To calculate the parallactic angle for another coordinate system pole, add the positionAngle between the J2000 system and the pole in the other coordinate system;

The machinery also needs a MeasFrame , with a position on Earth and a reference epoch. The reference time is necessary to have an epoch type.

The actual calculation of the parallactic angles is done by the operator() accepting a time or a list of times in various formats.

The machine calculates the paralaactic angle for the first time given to the machine. For subsequent times that are within a check interval, the angle is calculated assuming that only the hour angle changes within that interval. For moving objects the test interval is always forced to zero. Tests show that the machine with a zero interval is about 8 times faster than using brute force. Having an interval of an hour improves that by another factor of 4.
Tip: If the parallactic angles for a series of directions have to be calculated, it is best to have separate machines for each such field;

Example

Motivation

To speed up parallactic angle calculations

To Do

Definition at line 111 of file ParAngleMachine.h.

Constructor & Destructor Documentation

casa::ParAngleMachine::ParAngleMachine ( )

Create an empty machine.

It can only be used after appropriate 'set' methods

casa::ParAngleMachine::ParAngleMachine ( const MDirection & in )

Construct for the specified direction.

casa::ParAngleMachine::ParAngleMachine ( const ParAngleMachine & other )

Copy constructor (deep copy)

casa::ParAngleMachine::~ParAngleMachine ( )

Member Function Documentation

Double casa::ParAngleMachine::calcAngle ( const Double ep ) const [private]

Calculate position angle.

void casa::ParAngleMachine::init ( ) [private]

Initialise machinery.

void casa::ParAngleMachine::initConv ( ) const [private]

Initialise conversion.

Quantum<Vector<Double> > casa::ParAngleMachine::operator() ( const Quantum< Vector< Double > > & ep ) const

Return parallactic angles (epoch in days if given as Double)

Thrown Exceptions

AipsError if no frame or a frame without an Epoch (for type) or Position.

Quantum<Vector<Double> > casa::ParAngleMachine::operator() ( const Vector< MVEpoch > & ep ) const

Quantum<Vector<Double> > casa::ParAngleMachine::operator() ( const Vector< MEpoch > & ep ) const

Quantum<Double> casa::ParAngleMachine::operator() ( const Quantum< Double > & ep ) const

Quantum<Double> casa::ParAngleMachine::operator() ( const MVEpoch & ep ) const

Quantum<Double> casa::ParAngleMachine::operator() ( const MEpoch & ep ) const

Double casa::ParAngleMachine::operator() ( const Double & ep ) const

Vector<Double> casa::ParAngleMachine::operator() ( const Vector< Double > & ep ) const

ParAngleMachine& casa::ParAngleMachine::operator= ( const ParAngleMachine & other )

Copy assignments (deep copy)

Double casa::ParAngleMachine::posAngle ( const Quantum< Double > & ep ) const [private]

Get position angle (Epoch is supposed to be in days if Double)

Thrown Exceptions

AipsError if no frame or a frame without an Epoch (for type) or Position.

Vector<Double> casa::ParAngleMachine::posAngle ( const Quantum< Vector< Double > > & ep ) const [private]

Double casa::ParAngleMachine::posAngle ( const Double & ep ) const [private]

Vector<Double> casa::ParAngleMachine::posAngle ( const Vector< Double > & ep ) const [private]

void casa::ParAngleMachine::set ( const MDirection & in )

Will have a group of set methods (in direction; reference time; a frame; a reference time valid period.

void casa::ParAngleMachine::set ( const MeasFrame & frame )

void casa::ParAngleMachine::setInterval ( const Double ttime )

Set the test interval (in days) over which to use simple formula.

Member Data Documentation

Double casa::ParAngleMachine::clat1_p [mutable, private]

Definition at line 180 of file ParAngleMachine.h.

Double casa::ParAngleMachine::clat2_p [mutable, private]

Definition at line 182 of file ParAngleMachine.h.

MDirection::Convert* casa::ParAngleMachine::convdir_p [mutable, private]

Conversion engine.

Definition at line 161 of file ParAngleMachine.h.

Double casa::ParAngleMachine::defintvl_p [mutable, private]

Default time interval over which to do simple solution (days)

Definition at line 171 of file ParAngleMachine.h.

MeasFrame* casa::ParAngleMachine::frame_p [private]

Measure frame.

Definition at line 163 of file ParAngleMachine.h.

MDirection* casa::ParAngleMachine::indir_p [private]

Input direction.

Definition at line 159 of file ParAngleMachine.h.

Double casa::ParAngleMachine::intvl_p [mutable, private]

Time interval over which to do simple solution (days)

Definition at line 173 of file ParAngleMachine.h.

Double casa::ParAngleMachine::lastep_p [mutable, private]

Time of last full solution (in days)

Definition at line 169 of file ParAngleMachine.h.

Double casa::ParAngleMachine::longdiff_p [mutable, private]

Definition at line 178 of file ParAngleMachine.h.

Double casa::ParAngleMachine::longoff_p [mutable, private]

Definition at line 177 of file ParAngleMachine.h.

MVDirection casa::ParAngleMachine::mvdir_p [mutable, private]

Intermediate conversion result.

Definition at line 167 of file ParAngleMachine.h.

Double casa::ParAngleMachine::slat1_p [mutable, private]

Definition at line 179 of file ParAngleMachine.h.

Double casa::ParAngleMachine::slat2_p [mutable, private]

Definition at line 181 of file ParAngleMachine.h.

Double casa::ParAngleMachine::UTfactor_p [mutable, private]

Calculation cache.

Definition at line 176 of file ParAngleMachine.h.

MVDirection casa::ParAngleMachine::zenith_p [mutable, private]

Converted zenith.

Definition at line 165 of file ParAngleMachine.h.

The documentation for this class was generated from the following file:

casacore/measures/Measures/ParAngleMachine.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Intended use:

Review Status

Prerequisite

Etymology

Synopsis

Example

Motivation

To Do

Constructor & Destructor Documentation

Member Function Documentation

Thrown Exceptions

Thrown Exceptions

Member Data Documentation