astro
Class Astro

java.lang.Object
  astro.Astro

public class Astro
extends Object

Class Astro contains certain routines, that are everyday's need in an astronomer's life. All routines are static. Some methods are very old and use deprecated java methods.

Nested Class Summary

static class	Astro.Distance Prints out the distance between two points.
static class	Astro.HeliacalRise Prints the date when the sun rises with the target in Germany.
static class	Astro.Jd Prints out current jd or, if a parameter is given, the jd of the date given in the first argument.
static class	Astro.Mjd Prints out current jd or, if a parameter is given, the jd of the date given in the first argument.

Field Summary

static double	ACCURACY
static char	ARCMIN Char for arcminutes.
static char	ARCSEC Char for arcseconds.
static double	AU
static double	C
static double	COSEKL The cosine of the inclination of the eclitic.
static double	EKL Inclination of ecliptic in radians.
static double	JULIANCENTURY The number of days in a julian century.
private static DateFormat[]	KNOWN A mixture of different date parsers.
static double	MS100YEAR The number of ms in 100 years.
static double	MS1DAY The number of ms in a day.
static DateFormat	PARSE Default date parser.
static double	RFLUX Photon flux above atmosphere in R per 1m diameter (circular) per sec.
static double	SIDEREALYEAR The number of days in one sidereal year.
static double	SIDSOL Conversion factor from sidereal time to solar time.
static double	SINEKL The sine of the inclination of the eclitic.
static double	SOL_TO_SID Conversion factor from solar time to sidereal time.
static double	TROPICALYEAR The number of days in one tropical year.
static double	VFLUX Photon flux above atmosphere in V per 1m diameter (circular) per sec.

Constructor Summary

Astro()

Method Summary

static String	americanDate(double jd) Converts the julian date into a Date String following the American locale.
static Date	culminatesWhen(double ra) Returns the date at which the target culminated at local midnight in the year 2000.
static double	culminatesWith(double de, double phi) Calculates the culmination height of a target given the declination and longitude.
static double	distance(Position p1, Position p2) Calcualtes the distance of two sky positions, given by their ra and dec.
static Date	heliacalRise(double ra, double de, double lat, double h, double solh) Given a right ascension and a declination of the target, this method calculates the date when the object first reaches the target height for the given solar elevation.
static Date	heliacalRise(double ra, double de, double lat, double h, double solh, double sec) Given a right ascension and a declination of the target, this method calculates the date when the object first reaches its target height at least the stated number of seconds before the sun rises to the given solar elevation.
static Date	heliacalSet(double ra, double de, double lat, double h, double solh) Given a right ascension and a declination of the target, this method calculates the date when the object last reaches the target height for the given solar elevation.
static Date	heliacalSet(double ra, double de, double lat, double h, double solh, double sec) Given a right ascension and a declination of the target, this method calculates the date when the object last reaches the target height for the given solar elevation.
static double	JD(Date datum) Gets the julian date from a Dateobject.
static Date	JD(double jd) Converts the julian date into a Dateobject.
static double	JD(String datumstring) Gets the julian date from a date string.
static double	mjd(Date datum) Gets the modified julian date from a Dateobject.
static Date	mjd(double mjd) Converts the modified julian date into a Dateobject.
static double	mjd(String datumstring) Gets the modified julian date from a date string.
static double	overlap(double theta1, double span1, double theta2, double span2) Given two positions in a 24-h angle and given two half-intervals, this method returns the overlap.
static Date	riseWithSunRise(double ra, double de, double lat) Returns the date when a specified target at a specified latitude rises with the sun.
static Date	riseWithSunSet(double ra, double de, double lat) Returns the date when a specified target at a specified latitude rises with the sun.
static Date	setWithSunRise(double ra, double de, double lat) Returns the date when a specified target at a specified latitude rises with the sun.
static Date	setWithSunSet(double ra, double de, double lat) Returns the date when a specified target at a specified latitude rises with the sun.
static double	toLT(double jd, Location site) Converts a julian date to the local time.
private static Date	tryParse(String datumstring) We try various date parser and return the first successful one.
static double	visibleFor(double de, double phi, double h) Returns the time a target is visible in seconds.

Methods inherited from class java.lang.Object

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

Field Detail

EKL

public static final double EKL

Inclination of ecliptic in radians.

See Also:

Constant Field Values

SINEKL

public static final double SINEKL

The sine of the inclination of the eclitic.

See Also:

Constant Field Values

COSEKL

public static final double COSEKL

The cosine of the inclination of the eclitic.

See Also:

Constant Field Values

MS1DAY

public static final double MS1DAY

The number of ms in a day.

See Also:

Constant Field Values

MS100YEAR

public static final double MS100YEAR

The number of ms in 100 years.

See Also:

Constant Field Values

JULIANCENTURY

public static final double JULIANCENTURY

The number of days in a julian century.

See Also:

Constant Field Values

SIDEREALYEAR

public static final double SIDEREALYEAR

The number of days in one sidereal year.

See Also:

Constant Field Values

TROPICALYEAR

public static final double TROPICALYEAR

The number of days in one tropical year.

See Also:

Constant Field Values

SOL_TO_SID

public static final double SOL_TO_SID

Conversion factor from solar time to sidereal time.

See Also:

Constant Field Values

SIDSOL

public static final double SIDSOL

Conversion factor from sidereal time to solar time.

See Also:

Constant Field Values

AU

public static final double AU

See Also:

Constant Field Values

C

public static final double C

See Also:

Constant Field Values

VFLUX

public static final double VFLUX

Photon flux above atmosphere in V per 1m diameter (circular) per sec.

See Also:

Constant Field Values

RFLUX

public static final double RFLUX

Photon flux above atmosphere in R per 1m diameter (circular) per sec.

See Also:

Constant Field Values

ACCURACY

public static final double ACCURACY

See Also:

Constant Field Values

ARCSEC

public static final char ARCSEC

Char for arcseconds.

See Also:

Constant Field Values

ARCMIN

public static final char ARCMIN

Char for arcminutes.

See Also:

Constant Field Values

PARSE

public static final DateFormat PARSE

Default date parser.

KNOWN

private static final DateFormat[] KNOWN

A mixture of different date parsers.

Constructor Detail

Astro

public Astro()

Method Detail

JD

public static double JD(String datumstring)

Gets the julian date from a date string. Returned value is jd.fjd.

Parameters:

datumstring - The date as a string

Returns:

The jd as a double.

mjd

public static double mjd(String datumstring)

Gets the modified julian date from a date string. Returned value is jd.fjd.

Parameters:

datumstring - The date as a string

Returns:

The jd as a double.

tryParse

private static Date tryParse(String datumstring)

We try various date parser and return the first successful one.

JD

public static double JD(Date datum)

Gets the julian date from a Dateobject.

Parameters:

datum - The Date object

Returns:

The jd as a double.

mjd

public static double mjd(Date datum)

Gets the modified julian date from a Dateobject.

Parameters:

datum - The Date object

Returns:

The jd as a double.

mjd

public static Date mjd(double mjd)

Converts the modified julian date into a Dateobject.

Parameters:

mjd - The modified julian date as a double.

Returns:

The Date object matching the parameter mjd.

JD

public static Date JD(double jd)

Converts the julian date into a Dateobject.

Parameters:

jd - The julian date as a double.

Returns:

The Date object matching the parameter jd.

americanDate

public static String americanDate(double jd)

Converts the julian date into a Date String following the American locale.

Parameters:

jd - The julian date as a double.

Returns:

The date as an american-local String.

toLT

public static double toLT(double jd,
                          Location site)

Converts a julian date to the local time.

Parameters:

jd - The julian date (UT0).

site - The location of the observer

Returns:

double The local time in hours and fractional hours.

culminatesWith

public static double culminatesWith(double de,
                                    double phi)

Calculates the culmination height of a target given the declination and longitude. Returned value is in degrees.

Parameters:

de - Declination in degrees.

phi - Latitude in degrees.

Returns:

The culmination height in degrees.

visibleFor

public static double visibleFor(double de,
                                double phi,
                                double h)

Returns the time a target is visible in seconds.

Parameters:

de - Declination in degrees.

phi - Latitude in degrees.

culminatesWhen

public static Date culminatesWhen(double ra)

Returns the date at which the target culminated at local midnight in the year 2000. Strictly speaking, the day in the year 2000 is calculated when the sun had the opposition in right ascension to the target.

Parameters:

ra - Right ascension in degrees.

riseWithSunRise

public static Date riseWithSunRise(double ra,
                                   double de,
                                   double lat)

Returns the date when a specified target at a specified latitude rises with the sun.

Parameters:

ra - Right ascension of target in degrees.

de - Declination of target in degrees.

lat - Latitude of location in degrees.

riseWithSunSet

public static Date riseWithSunSet(double ra,
                                  double de,
                                  double lat)

Returns the date when a specified target at a specified latitude rises with the sun.

Parameters:

ra - Right ascension of target in degrees.

de - Declination of target in degrees.

lat - Latitude of location in degrees.

setWithSunRise

public static Date setWithSunRise(double ra,
                                  double de,
                                  double lat)

Returns the date when a specified target at a specified latitude rises with the sun.

Parameters:

ra - Right ascension of target in degrees.

de - Declination of target in degrees.

lat - Latitude of location in degrees.

setWithSunSet

public static Date setWithSunSet(double ra,
                                 double de,
                                 double lat)

Returns the date when a specified target at a specified latitude rises with the sun.

Parameters:

ra - Right ascension of target in degrees.

de - Declination of target in degrees.

lat - Latitude of location in degrees.

overlap

public static double overlap(double theta1,
                             double span1,
                             double theta2,
                             double span2)

Given two positions in a 24-h angle and given two half-intervals, this method returns the overlap. A target at ra1 with a visibility span of ± Δt1 can be intersected with a solar ra2 and a twilight span of Δt2 by taking into account that the sidereal time &theta1 = ra1 and &theta2 = ra2-12 and then issuing the numbers to this method.

Parameters:

theta1 - First (sidereal) time, any intervall

span1 - First half span, i.e. from theta1-span1 to theta1+span1

theta2 - Second (sidereal) time, any intervall

span2 - Second half span

Returns:

The overlap in hours.

heliacalRise

public static Date heliacalRise(double ra,
                                double de,
                                double lat,
                                double h,
                                double solh)

Given a right ascension and a declination of the target, this method calculates the date when the object first reaches the target height for the given solar elevation. For target and solar height zero, this method delivers the same as riseWithSunRise(double, double, double).

heliacalRise

public static Date heliacalRise(double ra,
                                double de,
                                double lat,
                                double h,
                                double solh,
                                double sec)

Given a right ascension and a declination of the target, this method calculates the date when the object first reaches its target height at least the stated number of seconds before the sun rises to the given solar elevation. For target and solar height zero, this method delivers the same as riseWithSunRise(double, double, double).

heliacalSet

public static Date heliacalSet(double ra,
                               double de,
                               double lat,
                               double h,
                               double solh)

Given a right ascension and a declination of the target, this method calculates the date when the object last reaches the target height for the given solar elevation. For target and solar height zero, this method delivers the same as setWithSunSet(double, double, double).

heliacalSet

public static Date heliacalSet(double ra,
                               double de,
                               double lat,
                               double h,
                               double solh,
                               double sec)

Given a right ascension and a declination of the target, this method calculates the date when the object last reaches the target height for the given solar elevation. For target and solar height zero, this method delivers the same as setWithSunSet(double, double, double).

distance

public static double distance(Position p1,
                              Position p2)

Calcualtes the distance of two sky positions, given by their ra and dec. The returned value is in degrees.

Returns:

-1 If either position is null, NaN if either position is invalid.