cds.astro
Class Astropos

java.lang.Object
  cds.astro.Coo
      cds.astro.Astrocoo
          cds.astro.Astropos

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class Astropos
extends Astrocoo
implements java.io.Serializable

The class Astropos adds to Astrocoo the notions of mouvement (proper motions, velocity) and error ellipses.

The edition of the position in an Astropos can be done in a StringBuffer (edit methods) with options like sexagesimal or decimal edition, or as a String with one of the available toString methods. In string format, an astropos looks like:
longitude +/- latitude (epoch) [errorEllipse_mas (meanEpoch)] pm_lon pm_lat [errorEllipse_mas/yr ] parallax_mas [error] radialVelocity_km/s [error]

The values are expressed internally as cartesian components in the associated frame. Errors are expressed internally as a 6x6 covariance matrix, (multinormal error distribution is asumed), also aligned with the frame main axes. Errors in other frames are computed using the property that, if x is multinormal with covariance matrix V then Tx is multinormal with covariance matrix TV^tT. For instance, the variation of the 6-vector (x,y,x,xd,yd,zd) with time is linear with the following T(t) matrix:

      1   0   0   t   0   0
      0   1   0   0   t   0
      0   0   1   0   0   t
      0   0   0   1   0   0
      0   0   0   0   1   0
      0   0   0   0   0   1
 

(notice that T^-1(t) = T(-t) and T(t₁) T(t₂) = T(t₁ + t₂)) and the error propagations are easily computed by this method.

Conversions into other frames (convertTo(cds.astro.Astroframe) method) imply a change of all parameters (position, proper motions, errors). A change of the epoch is achieved with the toEpoch(double) method.

Version:

1.0 03-Aug-2004, 1.1 03-Sep-2006

Author:

Francois Ochsenbein [CDS]

See Also:

Serialized Form

Field Summary

double	e_plx Mean error on parallax in mas
double	e_rv Mean error on radial Velocity in km/s
double	plx Parallax in mas
double	rv Radial velocity in km/s

Fields inherited from class cds.astro.Astrocoo

ARCMIN, ARCSEC, DEG, EDIT_2NUMBERS, EDIT_DEFAULT, EDIT_EPOCH, EDIT_FRAME, EDIT_FULL, EDIT_MEAN_EPOCH, epoch, frame, MAS, NONE

Fields inherited from class cds.astro.Coo

decimals, ed, Umatrix3, x, y, z

Constructor Summary

Astropos()
Create the default (empty) Astropos (ICRS)

Astropos(Astrocoo coo)
Create a Astropos object from an existing Astrocoo

Astropos(Astroframe frame)
Create an empty Astropos.

Astropos(Astroframe frame, double lon, double lat)
Create a Astropos object with just longitude + latitude

Astropos(Astroframe frame, double lon, double lat, double epoch, double[] eepos, double mu1, double mu2, double epocho, double[] eepm, double[] plx2, double[] rv2)
Set a Astropos from position + proper motion.

Astropos(Astroframe frame, double lon, double lat, double epoch, double mu1, double mu2)
Create a Astropos object: coordinates + proper motion.

Astropos(Astroframe frame, java.lang.String text)
Create an Astropos object from a position (Epoch)

Astropos(java.lang.String text)
Create an Astropos object from just a string.

Method Summary

java.lang.Object	clone() Clone the Coo object
void	convertTo(Astroframe new_frame) Transform the position into another frame.
boolean	copyErrorEllipse(double[] ee3) Get the Error Ellipse of the position
boolean	copyParallax(double[] valerr) Get the Parallax
boolean	copyProperMotion(double[] pm) Get the proper motions (2 components)
boolean	copyProperMotionErrorEllipse(double[] ee3) Get the Error Ellipse of the Proper Motion
boolean	copyVelocity(double[] valerr) Get the Velocity
void	dump(java.lang.String title) Dump the contents of an Astropos
boolean	equals(java.lang.Object o) Compare 2 coordinates.
static void	errorEllipseToVariance(double[] ee3, double[] var) Convert an error ellipse (a, b, posAngle) into a variance matrix (var(x), var(y), cov(x,y)).
double	getProperMotionLat() Get the Latitude proper motion (mas/yr)
double	getProperMotionLon() Get the Longitude proper motion (mas/yr)
double	normalize() Renormalize the vectors
int	parse(java.lang.String txt, int offset) Parsing method: interpret a String.
static boolean	parseErrorEllipse(Parsing txt, double[] ee3) Interpret an error ellipse written [ a b theta ].
boolean	parsing(Parsing txt) Interpret the string and convert to Coo + Epoch.
void	rotate(double[][] R) Rotate an Astropos.
void	set() Reset position to unknown.
void	set(Astrocoo coo) Set position from another Astrocoo
void	set(Coo coo) New position from a Coo
void	set(Coo coo, double epoch) Set position from Coordinate and Epoch.
void	set(double lon, double lat) Set position from RA + Dec.
void	set(double lon, double lat, double epoch) Set position from RA + Dec and epoch
void	set(double lon, double lat, double epoch, double[] eepos, double mu1, double mu2, double epocho, double[] eepm, double[] plx2, double[] rv2) Set a Astropos from position + proper motion.
void	set(double lon, double lat, double epoch, double mu1, double mu2) Set position from RA + Dec.
void	set(java.lang.String text) Set a particuliar set of positions in the Astropos.
void	set(java.lang.String text, boolean equatorial) Overload Coo method (see set(String text) )
void	setDefaultMeanEpoch(double epocho) Set a Default Mean Epoch.
boolean	setEpoch(double epoch) Set the Epoch of the position.
boolean	setErrorEllipse(double e_maj, double e_min, double pa) Set the Error Ellipse.
boolean	setErrorEllipse(double e_maj, double e_min, double pa, double epocho) Set the Error Ellipse, with the epoch of this error (epocho, mean epoch)
boolean	setErrorProperMotion(double e_mu1, double e_mu2) Set the Error on Proper Motion
boolean	setErrorProperMotion(double e_maj, double e_min, double pa) Set the Error on Proper Motions
void	setFrameEpoch() Set the default epoch of the frame to current epoch
boolean	setParallax(double plx, double err) Set the Parallax
boolean	setProperMotion(double mu1, double mu2) Set the Proper Motion
boolean	setRadialVelocity(double rv, double err) Set the Radial Velocity
double	sigmaLat() Get the mean error on Latitude ({sigma}(Dec))
double	sigmaLon() Get the mean error on Longitude ({sigma}RA*cos(Dec))
double	sigmaProperMotionLat() Get the mean error on Latitude proper motion ({sigma}(Dec))
double	sigmaProperMotionLon() Get the mean error on Longitude proper motion ({sigma}pmRA*cos(Dec))
void	toEpoch(double Jyr) Change the epoch of the position (in the same frame)
java.lang.String	toString() Default edition: use what's stored
java.lang.String	toString(int opt) Default edition: use what's stored
static void	varianceToErrorEllipse(double[] var, double[] ee3) Convert a variance matrix (var(x), var(y), cov(x,y)) into an error ellipse (a, b, posAngle).

Methods inherited from class cds.astro.Astrocoo

convert, edit, editingOptions, explain, getEditing, getEpoch, getFrame, getLatPrec, getLonPrec, getPrecision, parseFrame, setEditing, setPrecision, setPrecision, toString

Methods inherited from class cds.astro.Coo

add, add, copyAngles, copyUvector, distance, distance, editCoo, eulerMatrix, getLat, getLon, localMatrix, localMatrix, localMatrix, moveMatrix, normalize, rotate_1, rotateVector_1, rotateVector, setDecimals, setUvec, sub, sub

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

plx

public double plx

Parallax in mas

rv

public double rv

Radial velocity in km/s

e_plx

public double e_plx

Mean error on parallax in mas

e_rv

public double e_rv

Mean error on radial Velocity in km/s

Constructor Detail

Astropos

public Astropos()

Create the default (empty) Astropos (ICRS)

Astropos

public Astropos(Astroframe frame)

Create an empty Astropos.

Parameters:

frame - in which frame

Astropos

public Astropos(Astroframe frame,
                double lon,
                double lat)

Create a Astropos object with just longitude + latitude

Parameters:

lon - longitude (RA), degrees

lat - latitude (Dec), degrees

Astropos

public Astropos(Astroframe frame,
                double lon,
                double lat,
                double epoch,
                double mu1,
                double mu2)

Create a Astropos object: coordinates + proper motion.

Parameters:

lon - longitude (RA), degrees

lat - latitude (Dec), degrees

epoch - epoch of the longitude/latitude, year

mu1 - proper motion along longitude, mas/yr

mu2 - proper motion along latitude, mas/yr

Astropos

public Astropos(Astrocoo coo)

Create a Astropos object from an existing Astrocoo

Parameters:

coo - Astrocoo object

Astropos

public Astropos(Astroframe frame,
                java.lang.String text)
         throws java.text.ParseException

Create an Astropos object from a position (Epoch)

Parameters:

frame - one of the possible Astroframes

text - Text with position, possibly followed by an epoch

Throws:

java.text.ParseException

Astropos

public Astropos(java.lang.String text)
         throws java.text.ParseException

Create an Astropos object from just a string.

Parameters:

text - Text with frame, position, possibly followed by an epoch

Throws:

java.text.ParseException

Astropos

public Astropos(Astroframe frame,
                double lon,
                double lat,
                double epoch,
                double[] eepos,
                double mu1,
                double mu2,
                double epocho,
                double[] eepm,
                double[] plx2,
                double[] rv2)

Set a Astropos from position + proper motion.

Parameters:

frame - one of the possible Astroframes

lon - longitude (RA), degrees

lat - latitude (Dec), degrees

eepos - error ellipse, mas

epoch - epoch of the longitude/latitude, Julian year

mu1 - proper motion along longitude, mas/yr

mu2 - proper motion along latitude, mas/yr

eepm - error ellipse of proper motion, mas/yr

epocho - epoch of position error (minimal error), Jyr

plx2 - parallax + its error (mas)

rv2 - radial velocity + its error (km/s)

Method Detail

normalize

public double normalize()

Renormalize the vectors

Overrides:

normalize in class Coo

Returns:

the norm of the 3-D vector

rotate

public final void rotate(double[][] R)

Rotate an Astropos. Its changes position, proper motions and errors

Overrides:

rotate in class Coo

Parameters:

R - [3][3] matrix

varianceToErrorEllipse

public static final void varianceToErrorEllipse(double[] var,
                                                double[] ee3)

Convert a variance matrix (var(x), var(y), cov(x,y)) into an error ellipse (a, b, posAngle). The axises of the error ellipse are the squared eigenvalues of variance matrix, i.e.
(var(x)-a)(var(y)-a) = cov(x,y)
(var(x)-b)(var(y)-b) = cov(x,y)
a² and b² are solutions of a simple 2nd order equation. The posAngle defines the eigenvector of the largest eigenvalue

Parameters:

var - Vector {var(x) var(y) cov(x,y) }

ee3 - Vector { a b theta } axises+PA of ellipse The relation

errorEllipseToVariance

public static final void errorEllipseToVariance(double[] ee3,
                                                double[] var)

Convert an error ellipse (a, b, posAngle) into a variance matrix (var(x), var(y), cov(x,y)). X = sin(theta)*x - cos(theta)*y = st*x - ct*y
Y = cos(theta)*x + sin(theta)*y = ct*x + st*y
the covariances of (X,Y) are:
var(X) = st²*var(x) + ct²*var(y)
var(Y) = ct²*var(x) + st²*var(y)
cov(X,Y) = ct*st*(var(x)-var(y))

Parameters:

ee3 - Vector { a b theta} axises+PA of ellipse

var - Vector {var(x) var(y) cov(x,y)} The relation

parseErrorEllipse

public static boolean parseErrorEllipse(Parsing txt,
                                        double[] ee3)

Interpret an error ellipse written [ a b theta ]. If theta is missing, its value is defaulted to 90° (i.e. a and b represent the mean errors on RA*cos(Dec) and Dec). If a single number is found, it's assumed to be the error circle.

Parameters:

txt - Text to interpret

ee3 - Vector ( a b theta) axises+PA of ellipse

Returns:

true if error ellipse could be parsed.

clone

public java.lang.Object clone()

Description copied from class: Coo

Clone the Coo object

Overrides:

clone in class Astrocoo

dump

public void dump(java.lang.String title)

Dump the contents of an Astropos

Overrides:

dump in class Astrocoo

Parameters:

title - title line

parsing

public boolean parsing(Parsing txt)

Interpret the string and convert to Coo + Epoch. Called from set and parse routines. Interprets until mismatch.

Overrides:

parsing in class Astrocoo

Parameters:

txt - to interpret as a Parsing object e.g. "12 34.5 -72 54 [30 20 65 (J1991.25)] J2000.0 +125.2 -35.2 [3.9 2.5 45] 123[4]km/s 10[5]"

Returns:

true if OK.

parse

public int parse(java.lang.String txt,
                 int offset)

Parsing method: interpret a String.

Overrides:

parse in class Astrocoo

Parameters:

txt - to interpret.

offset - starting position in text

Returns:

new position.

set

public void set()

Reset position to unknown.

Overrides:

set in class Coo

set

public void set(Coo coo)

New position from a Coo

Overrides:

set in class Coo

Parameters:

coo - A coordinate

set

public void set(Astrocoo coo)

Set position from another Astrocoo

Overrides:

set in class Astrocoo

Parameters:

coo - A coordinate

set

public void set(Coo coo,
                double epoch)

Set position from Coordinate and Epoch.

Overrides:

set in class Astrocoo

Parameters:

coo - A coordinate

epoch - Epoch of position

set

public void set(double lon,
                double lat)

Set position from RA + Dec.

Overrides:

set in class Coo

Parameters:

lon - longitude in degrees

lat - latitude angle in degrees

set

public void set(double lon,
                double lat,
                double epoch)

Set position from RA + Dec and epoch

Overrides:

set in class Coo

Parameters:

lon - x item in unit vector (direction cosines)

lat - y item in unit vector (direction cosines)

epoch - z item in unit vector (direction cosines)

set

public void set(double lon,
                double lat,
                double epoch,
                double mu1,
                double mu2)

Set position from RA + Dec.

set

public void set(double lon,
                double lat,
                double epoch,
                double[] eepos,
                double mu1,
                double mu2,
                double epocho,
                double[] eepm,
                double[] plx2,
                double[] rv2)

Set a Astropos from position + proper motion. To remove ?

Parameters:

lon - longitude (RA), degrees

lat - latitude (Dec), degrees

epoch - epoch of the longitude/latitude, year

eepos - error ellipse, mas

mu1 - proper motion along longitude, mas/yr

mu2 - proper motion along latitude, mas/yr

epocho - epoch of proper motion (minimal position error)

eepm - error ellipse of proper motion, mas/yr

plx2 - parallax + its error (mas)

rv2 - radial velocity + its error (km/s)

set

public void set(java.lang.String text)
         throws java.text.ParseException

Set a particuliar set of positions in the Astropos. The precision is adapted to the number of significant digits existing in the input text string.

Overrides:

set in class Astrocoo

Parameters:

text - Longitude + latitude in text

Throws:

java.text.ParseException - when the string is not interpretable

set

public void set(java.lang.String text,
                boolean equatorial)
         throws java.text.ParseException

Overload Coo method (see set(String text) )

Throws:

java.text.ParseException

setFrameEpoch

public void setFrameEpoch()

Set the default epoch of the frame to current epoch

setDefaultMeanEpoch

public void setDefaultMeanEpoch(double epocho)

Set a Default Mean Epoch. (e.g. 1991.25 for Hipparcos data)

Parameters:

epocho - The default mean epoch, in Julian years. An NaNvalue remove the default mean epoch.

setEpoch

public boolean setEpoch(double epoch)

Set the Epoch of the position.

Overrides:

setEpoch in class Astrocoo

Parameters:

epoch - The epoch of the positions. An NaNvalue remove the default mean epoch.

Returns:

true when parameter OK, false if ignored.

setErrorEllipse

public boolean setErrorEllipse(double e_maj,
                               double e_min,
                               double pa)

Set the Error Ellipse. Note that the position MUST have been set before, otherwise this parameter is ignored...

Parameters:

e_maj - Major axis of error ellipse (mas)

e_min - Minor axis of error ellipse (mas

pa - Position angle of error ellipse (deg)

Returns:

true when parameter OK, false if positions not known.

setErrorEllipse

public boolean setErrorEllipse(double e_maj,
                               double e_min,
                               double pa,
                               double epocho)

Set the Error Ellipse, with the epoch of this error (epocho, mean epoch)

Parameters:

e_maj - Major axis of error ellipse (mas)

e_min - Minor axis of error ellipse (mas

pa - Position angle of error ellipse (deg)

epocho - Mean epoch (epoch of the error)

Returns:

true when parameter OK, false if positions not known.

setProperMotion

public boolean setProperMotion(double mu1,
                               double mu2)

Set the Proper Motion

Parameters:

mu1 - Proper motion along longitude or Right Ascension (mas/yr)

mu2 - Proper motion along latitude or Declination (mas/yr)

Returns:

true when parameter OK, false if positions not known.

setErrorProperMotion

public boolean setErrorProperMotion(double e_mu1,
                                    double e_mu2)

Set the Error on Proper Motion

Parameters:

e_mu1 - Error on longitude or Right Ascension (mas/yr)

e_mu2 - Error on latitude or Declination (mas/yr)

Returns:

true when parameter OK, false if positions not known.

setErrorProperMotion

public boolean setErrorProperMotion(double e_maj,
                                    double e_min,
                                    double pa)

Set the Error on Proper Motions

Parameters:

e_maj - Major axis of error ellipse (mas)

e_min - Minor axis of error ellipse (mas

pa - Position angle of error ellipse (deg)

Returns:

true when parameter OK, false if positions not known.

setRadialVelocity

public boolean setRadialVelocity(double rv,
                                 double err)

Set the Radial Velocity

Parameters:

rv - Radial velocity in km/s

err - Error on radial velocity in km/s

Returns:

true when parameter OK, false if positions not known.

setParallax

public boolean setParallax(double plx,
                           double err)

Set the Parallax

Parameters:

plx - Parallax, in mas (kpc^-1)

err - Error on parallax (mas)

Returns:

true when parameter OK, false if positions not known.

copyErrorEllipse

public boolean copyErrorEllipse(double[] ee3)

Get the Error Ellipse of the position

Parameters:

ee3 - Vector of 3 components (a, b, posAngle) (a and b in mas, posAngle in degrees)

Returns:

true for actual error ellipse, false for estimated one.

sigmaLon

public double sigmaLon()

Get the mean error on Longitude ({sigma}RA*cos(Dec))

Returns:

The mean error (estimated or actual) in mas

sigmaLat

public double sigmaLat()

Get the mean error on Latitude ({sigma}(Dec))

Returns:

The mean error (estimated or actual) in mas

copyProperMotion

public boolean copyProperMotion(double[] pm)

Get the proper motions (2 components)

Parameters:

pm - Vector of 2 components (pmRA*cos(Dec), pmDec)

Returns:

true for actual proper motion, false for estimated one.

getProperMotionLon

public double getProperMotionLon()

Get the Longitude proper motion (mas/yr)

Returns:

Proper motion in Longitude (RA), in mas/yr

getProperMotionLat

public double getProperMotionLat()

Get the Latitude proper motion (mas/yr)

Returns:

Proper motion in Latitude (Dec), in mas/yr

copyProperMotionErrorEllipse

public boolean copyProperMotionErrorEllipse(double[] ee3)

Get the Error Ellipse of the Proper Motion

Parameters:

ee3 - Vector of 3 components (a, b, posAngle) (a and b in mas/Jyr, posAngle in degrees)

Returns:

true for actual error ellipse, false for estimated one.

sigmaProperMotionLon

public double sigmaProperMotionLon()

Get the mean error on Longitude proper motion ({sigma}pmRA*cos(Dec))

Returns:

The mean error (estimated or actual) in mas/yr

sigmaProperMotionLat

public double sigmaProperMotionLat()

Get the mean error on Latitude proper motion ({sigma}(Dec))

Returns:

The mean error (estimated or actual) in mas

copyParallax

public boolean copyParallax(double[] valerr)

Get the Parallax

Parameters:

valerr - Vector of 2 components (plx, e_plx) (mas)

Returns:

true for actual parallax, false for estimated one.

copyVelocity

public boolean copyVelocity(double[] valerr)

Get the Velocity

Parameters:

valerr - Vector of 2 components (Rvel, e_Rvel) (mas)

Returns:

true for actual parallax, false for estimated one.

equals

public boolean equals(java.lang.Object o)

Compare 2 coordinates.

Overrides:

equals in class Astrocoo

Parameters:

o - Objet a comparer.

Returns:

Vrai si o est identique a this.

toString

public java.lang.String toString()

Default edition: use what's stored

Overrides:

toString in class Astrocoo

Returns:

the edited string

toString

public java.lang.String toString(int opt)

Default edition: use what's stored

Overrides:

toString in class Astrocoo

Parameters:

opt - Option, as in Astrocoo

Returns:

the edited string

toEpoch

public void toEpoch(double Jyr)

Change the epoch of the position (in the same frame)

Parameters:

Jyr - the new epoch

convertTo

public void convertTo(Astroframe new_frame)

Transform the position into another frame. On return, all astrometric components are converted into the new frame specified, at the default epoch of new_frame.

Overrides:

convertTo in class Astrocoo

Parameters:

new_frame - The frame of the resulting position.