astro

Class MoonPosition

java.lang.Object

astro.MoonPosition

public class MoonPosition
extends Object

A class calculating the position of the moon. It is based on the AstroLib package provided by Mark Huss. He gives no hint about the precision of the formulas used, but from a first test I estimate an accuracy of down to one arc minute.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MoonPosition.Test Testing purpose mainly.

Field Summary

Fields

Modifier and Type	Field and Description
private double	dec The declination of the moon.
private Lunar	moon The helper object calculating the moon position.
private double	ra The right ascension of the moon.
private boolean	radecvalid True if ra,dec are valid.
private Date	when The date for which the moon position is valid.

Constructor Summary

Constructors

Constructor and Description
MoonPosition() Constructs a new moon position object.
MoonPosition(Date fordate) Constructs a new moon position object for the given date.

Method Summary

Modifier and Type	Method and Description
private void	calcRaDec() Calculates the right ascension and the declination of the moon.
double	getDec() Returns the declination of the moon for the center of the earth in radians.
double	getDistance() Returns the distance to the moon in kilometers.
double	getIlluminatedFraction()
double	getLatitude() Returns the ecliptical latitude of the moon for the center of the earth in radians.
double	getLongitude() Returns the ecliptical longitude of the moon for the center of the earth in radians.
double	getRa() Returns the right ascension of the moon for the center of the earth in radians.
void	setDate(Date fordate) Sets a (new) date for the moon position object.

Methods inherited from class java.lang.Object

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

Field Detail

when

private Date when

The date for which the moon position is valid.

moon

private Lunar moon

The helper object calculating the moon position.

ra

private double ra

The right ascension of the moon.

dec

private double dec

The declination of the moon.

radecvalid

private boolean radecvalid

True if ra,dec are valid.

Constructor Detail

MoonPosition

public MoonPosition()

Constructs a new moon position object. The position data may only be retrieved after a date was set.

MoonPosition

public MoonPosition(Date fordate)

Constructs a new moon position object for the given date. Data retrieval may proceed at once.

Method Detail

setDate

public void setDate(Date fordate)

Sets a (new) date for the moon position object. Right ascension and declination are invalidated.

getLongitude

public double getLongitude()

Returns the ecliptical longitude of the moon for the center of the earth in radians.

Throws:

IllegalArgumentException - If no date was set.

getLatitude

public double getLatitude()

Returns the ecliptical latitude of the moon for the center of the earth in radians.

Throws:

IllegalArgumentException - If no date was set.

getRa

public double getRa()

Returns the right ascension of the moon for the center of the earth in radians.

Throws:

IllegalArgumentException - If no date was set.

getDec

public double getDec()

Returns the declination of the moon for the center of the earth in radians.

Throws:

IllegalArgumentException - If no date was set.

getDistance

public double getDistance()

Returns the distance to the moon in kilometers.

Throws:

IllegalArgumentException - If no date was set.

getIlluminatedFraction

public double getIlluminatedFraction()

calcRaDec

private void calcRaDec()

Calculates the right ascension and the declination of the moon. Stores both values for later retrieval.