net.grelf.astro

Class Topocentre

java.lang.Object

net.grelf.astro.Topocentre

public class Topocentre
extends java.lang.Object

Representing locations on the Earth's surface, objects of this class are responsible for transforming from geocentric to topocentric coordinates. Some places are predefined as constants in this class but it is easy to construct others.

Field Summary

Fields

Modifier and Type	Field and Description
static Topocentre	BELFAST
static Topocentre	EDINBURGH
static Topocentre	GREENWICH
static Topocentre	LONDON
static Topocentre	MANCHESTER
static Topocentre	NEWCASTLE
static Topocentre	WICK

Constructor Summary

Constructors

Constructor and Description
Topocentre(java.lang.String name, double longitudeDegs, double latitudeDegs, double heightM) We adopt Jean Meeus' convention: longitude is positive to the west of Greenwich; height is above sea level, in metres.

Method Summary

Modifier and Type	Method and Description
SkyPoint	adjust(SkyPoint geocentric, double deltaAU, JulianDate jd) Adjust the given geocentric SkyPoint of an object at distance deltaAU (in astronomical units) to its topocentric value, ie as seen from this Topocentre at the given time.
double	calcAltitudeDegs(SkyPoint pt, JulianDate jd) Calculate the altitude of the given SkyPoint above the local horizon at the given time.
double	calcAzimuthDegs(SkyPoint pt, JulianDate jd) Calculate the azimuth (measured from South via West) of the given SkyPoint above the local horizon at the given time.
protected double	getCosPhi() For unit testing
double	getHeight() Height above sea level, in metres.
Angle	getLatitude()
Angle	getLongitude()
java.lang.String	getName()
protected double	getRhoCosPhiDash() For unit testing
protected double	getRhoSinPhiDash() For unit testing
protected double	getSinPhi() For unit testing

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

BELFAST

public static final Topocentre BELFAST

EDINBURGH

public static final Topocentre EDINBURGH

GREENWICH

public static final Topocentre GREENWICH

LONDON

public static final Topocentre LONDON

MANCHESTER

public static final Topocentre MANCHESTER

NEWCASTLE

public static final Topocentre NEWCASTLE

WICK

public static final Topocentre WICK

Constructor Detail

Topocentre

public Topocentre(java.lang.String name,
                  double longitudeDegs,
                  double latitudeDegs,
                  double heightM)

We adopt Jean Meeus' convention: longitude is positive to the west of Greenwich; height is above sea level, in metres.

Method Detail

getName

public java.lang.String getName()

getLongitude

public Angle getLongitude()

getLatitude

public Angle getLatitude()

getHeight

public double getHeight()

Height above sea level, in metres.

getSinPhi

protected double getSinPhi()

For unit testing

getCosPhi

protected double getCosPhi()

For unit testing

getRhoSinPhiDash

protected double getRhoSinPhiDash()

For unit testing

getRhoCosPhiDash

protected double getRhoCosPhiDash()

For unit testing

adjust

public SkyPoint adjust(SkyPoint geocentric,
                       double deltaAU,
                       JulianDate jd)

Adjust the given geocentric SkyPoint of an object at distance deltaAU (in astronomical units) to its topocentric value, ie as seen from this Topocentre at the given time.

calcAltitudeDegs

public double calcAltitudeDegs(SkyPoint pt,
                               JulianDate jd)

Calculate the altitude of the given SkyPoint above the local horizon at the given time. Algorithm from Jean Meeus, Astronomical Algorithms, p93.

calcAzimuthDegs

public double calcAzimuthDegs(SkyPoint pt,
                              JulianDate jd)

Calculate the azimuth (measured from South via West) of the given SkyPoint above the local horizon at the given time. Algorithm from Jean Meeus, Astronomical Algorithms, p93.