jephem.astro.spacetime
Class Time

java.lang.Object
  |
  +--jephem.astro.spacetime.Time

All Implemented Interfaces:

TimeConstants

public abstract class Time

extends java.lang.Object

implements TimeConstants

Contains static methods used when dealing with time.
Related constants can be found in TimeConstants.

Field Summary

static java.lang.String[]

ENGLISH_TIMEFRAME_NAMES Contains the english names of time frames ; use constants UTC or TT_TDB of this interface to access to the names.

Fields inherited from interface jephem.astro.spacetime.TimeConstants

DAYS_PER_CENTURY, DAYS_PER_MILLENIUM, DAYS_PER_YEAR, JD1900, JD2000, JD2100, SECONDS_PER_DAY, TT_TDB, UTC

Constructor Summary

Time()

Method Summary

static double	calcDeltaT(double utc) Returns the value deltaT = TAI - UTC, in seconds.
static double	calcMjd(double jd) Returns the 'Modified Julian Day', number of Julian Days elapsed since November 17 1858, 00:00:00.
static java.lang.String	getTimeFrameLabel(int timeFrameIndex) Returns the english names of time frames ; use constants UTC or TT_TDB of TimeConstants to access to the names.
static double	getTT(double utc) Computes TT from UTC, using the formula TT = UTC + 32.184s + deltaT.
static double	getUTC(double tt) Computes UTC from TT, using the formula UTC = TT - 32.184s - deltaT.

Methods inherited from class java.lang.Object

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

Field Detail

ENGLISH_TIMEFRAME_NAMES

public static final java.lang.String[] ENGLISH_TIMEFRAME_NAMES

Contains the english names of time frames ; use constants UTC or TT_TDB of this interface to access to the names.

Constructor Detail

Time

public Time()

Method Detail

calcDeltaT

public static double calcDeltaT(double utc)

Returns the value deltaT = TAI - UTC, in seconds.
UTC stands for "Universal Coordinated Time", which is the basis of legal time.
TAI stands for "Temps Atomique International" (Atomic International Time).

Parameters:

utc - A UTC date expressed in Julian Days.

Returns:

The value of delatT, in seconds.

calcMjd

public static double calcMjd(double jd)

Returns the 'Modified Julian Day', number of Julian Days elapsed since November 17 1858, 00:00:00.
MJD = JD - 2400000.5.

Parameters:

jd - A date expressed in Julian Days.

getTimeFrameLabel

public static java.lang.String getTimeFrameLabel(int timeFrameIndex)

Returns the english names of time frames ; use constants UTC or TT_TDB of TimeConstants to access to the names.

getTT

public static double getTT(double utc)

Computes TT from UTC, using the formula TT = UTC + 32.184s + deltaT.
UTC stands for "Universal Coordinated Time", which is the basis of legal time.
TT stands for "Terrestrial Time", which is considered as equal to TDB, generally used in planetary theories.

Parameters:

utc - A UTC date expressed in Julian Days.

Returns:

The date in Terrestrial Time corresponding to 'utc', in julian days.

getUTC

public static double getUTC(double tt)

Computes UTC from TT, using the formula UTC = TT - 32.184s - deltaT.
TT stands for "Terrestrial Time", which is considered as equal to TDB, generally used
UTC stands for "Universal Coordinated Time", which is the basis of legal time. in planetary theories.

Returns:

The date in Terrestrial Time corresponding to 'utc', in julian days.