JulianDay (Time4J-Base 5.8 API)

java.lang.Object
- net.time4j.calendar.astro.JulianDay

All Implemented Interfaces:

Serializable
```
public final class JulianDay
extends Object
implements Serializable
```
The Julian day is the Julian day number for the preceding noon plus the fraction of the day (counting 86400 seconds) since that instant.

A Julian day number is defined as continuous number associated with the solar day and is zero at Greenwich mean noon on 1st of January 4713 BC. Important: Julian days are mainly used by astronomers and have nothing to do with the Julian calendar. See also the authoritative definition of IAU.

Note: The range of this class is limited to the year range of roughly -2000/+3000 because the precision will strongly decrease beyond those limits.

Since:

3.33/4.28

Author:

Meno Hochschild

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`MAX` The maximum value which corresponds roughly to the year `+3000`.
`static double`	`MIN` The minimum value which corresponds roughly to the year `-2000`.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object obj)`
`double`	`getCenturyJ2000()` Obtains the value of this Julian day as Julian century relative to the year 2000.
`double`	`getMJD()` Obtains the value of this Julian day as Modified Julian Date starting at midnight.
`TimeScale`	`getScale()` Obtains the underlying time scale.
`double`	`getValue()` Obtains the value of this Julian day starting at noon.
`int`	`hashCode()`
`JulianDay`	`minusDays(double amount)` Subtracts an amount in decimal days from this Julian day.
`JulianDay`	`minusSeconds(double amount)` Subtracts an amount in decimal seconds from this Julian day.
`static JulianDay`	`ofEphemerisTime(CalendarDate date, PlainTime time, ZonalOffset offset)` Creates a Julian day on the time scale `TimeScale.TT`, sometimes also called Julian Ephemeris Day.
`static JulianDay`	`ofEphemerisTime(double value)` Creates a Julian day on the time scale `TimeScale.TT`, sometimes also called Julian Ephemeris Day.
`static JulianDay`	`ofEphemerisTime(Moment moment)` Creates a Julian day on the time scale `TimeScale.TT`, sometimes also called Julian Ephemeris Day.
`static JulianDay`	`ofMeanSolarTime(double value)` Creates a Julian day on the time scale `TimeScale.UT`, hence related to the mean solar time.
`static JulianDay`	`ofMeanSolarTime(Moment moment)` Creates a Julian day on the time scale `TimeScale.UT`, hence related to the mean solar time.
`static JulianDay`	`ofSimplifiedTime(double value)` Creates a Julian day on the time scale `TimeScale.POSIX`.
`static JulianDay`	`ofSimplifiedTime(Moment moment)` Creates a Julian day on the time scale `TimeScale.POSIX`.
`JulianDay`	`plusDays(double amount)` Adds an amount in decimal days to this Julian day.
`JulianDay`	`plusSeconds(double amount)` Adds an amount in decimal seconds to this Julian day.
`Moment`	`toMoment()` Converts this Julian day to a `Moment`.
`String`	`toString()`

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - MIN
```
public static final double MIN
```
    The minimum value which corresponds roughly to the year -2000.
    
    See Also:
    
    Constant Field Values
  - MAX
```
public static final double MAX
```
    The maximum value which corresponds roughly to the year +3000.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - ofEphemerisTime
```
public static JulianDay ofEphemerisTime(double value)
```
    Creates a Julian day on the time scale TimeScale.TT, sometimes also called Julian Ephemeris Day.
    
    This kind of Julian day represents the actual astronomical standard. The time TT-2000-01-01T12:00Z corresponds to JD(TT)2451545.0
    
    Parameters:
    
    value - floating decimal value in range 990575.0 - 2817152.0
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if given value is not a finite number or out of range
  - ofEphemerisTime
```
public static JulianDay ofEphemerisTime(Moment moment)
```
    Creates a Julian day on the time scale TimeScale.TT, sometimes also called Julian Ephemeris Day.
    
    This kind of Julian day represents the actual astronomical standard. The time TT-2000-01-01T12:00Z corresponds to JD(TT)2451545.0
    
    Parameters:
    
    moment - corresponding moment
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if the Julian day of moment is not in supported range
  - ofEphemerisTime
```
public static JulianDay ofEphemerisTime(CalendarDate date,
                                        PlainTime time,
                                        ZonalOffset offset)
```
    Creates a Julian day on the time scale TimeScale.TT, sometimes also called Julian Ephemeris Day.
    
    This kind of Julian day represents the actual astronomical standard. The time TT-2000-01-01T12:00Z corresponds to JD(TT)2451545.0
    
    Parameters:
    
    date - calendar date
    
    time - local time
    
    offset - timezone offset
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if the Julian day of moment is not in supported range
    
    Since:
    
    3.36/4.31
  - ofMeanSolarTime
```
public static JulianDay ofMeanSolarTime(double value)
```
    Creates a Julian day on the time scale TimeScale.UT, hence related to the mean solar time.
    
    The conversion to the ephemeris time requires a delta-T-correction.
    
    Parameters:
    
    value - floating decimal value in range 990575.0 - 2817152.0
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if given value is not a finite number or out of range
  - ofMeanSolarTime
```
public static JulianDay ofMeanSolarTime(Moment moment)
```
    Creates a Julian day on the time scale TimeScale.UT, hence related to the mean solar time.
    
    The conversion to the ephemeris time requires a delta-T-correction.
    
    Parameters:
    
    moment - corresponding moment
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if the Julian day of moment is not in supported range
  - ofSimplifiedTime
```
public static JulianDay ofSimplifiedTime(double value)
```
    Creates a Julian day on the time scale TimeScale.POSIX.
    
    This conversion does not involve a delta-T-correction.
    
    Parameters:
    
    value - floating decimal value in range 990575.0 - 2817152.0
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if given value is not a finite number or out of range
    
    Since:
    
    3.34/4.29
  - ofSimplifiedTime
```
public static JulianDay ofSimplifiedTime(Moment moment)
```
    Creates a Julian day on the time scale TimeScale.POSIX.
    
    This conversion does not involve a delta-T-correction.
    
    Parameters:
    
    moment - corresponding moment
    
    Returns:
    
    JulianDay
    
    Throws:
    
    IllegalArgumentException - if the Julian day of moment is not in supported range
    
    Since:
    
    3.34/4.29
  - getValue
```
public double getValue()
```
    Obtains the value of this Julian day starting at noon.
    
    Returns:
    
    double
  - getMJD
```
public double getMJD()
```
    Obtains the value of this Julian day as Modified Julian Date starting at midnight.
    
    Returns:
    
    double
    
    See Also:
    
    EpochDays.MODIFIED_JULIAN_DATE
  - getCenturyJ2000
```
public double getCenturyJ2000()
```
    Obtains the value of this Julian day as Julian century relative to the year 2000.
    
    Returns:
    
    Julian century in J2000-frame
    
    Since:
    
    3.36/4.31
  - getScale
```
public TimeScale getScale()
```
    Obtains the underlying time scale.
    
    Returns:
    
    TimeScale
  - plusDays
```
public JulianDay plusDays(double amount)
```
    Adds an amount in decimal days to this Julian day.
    
    Parameters:
    
    amount - the amount in decimal days
    
    Returns:
    
    new adjusted instance of Julian day with the same time scale
  - minusDays
```
public JulianDay minusDays(double amount)
```
    Subtracts an amount in decimal days from this Julian day.
    
    Parameters:
    
    amount - the amount in decimal days
    
    Returns:
    
    new adjusted instance of Julian day with the same time scale
  - plusSeconds
```
public JulianDay plusSeconds(double amount)
```
    Adds an amount in decimal seconds to this Julian day.
    
    Parameters:
    
    amount - the amount in decimal seconds
    
    Returns:
    
    new adjusted instance of Julian day with the same time scale
  - minusSeconds
```
public JulianDay minusSeconds(double amount)
```
    Subtracts an amount in decimal seconds from this Julian day.
    
    Parameters:
    
    amount - the amount in decimal seconds
    
    Returns:
    
    new adjusted instance of Julian day with the same time scale
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - toMoment
```
public Moment toMoment()
```
    Converts this Julian day to a Moment.
    
    Returns:
    
    Moment

Class JulianDay

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MIN

MAX

Method Detail

ofEphemerisTime

ofEphemerisTime

ofEphemerisTime

ofMeanSolarTime

ofMeanSolarTime

ofSimplifiedTime

ofSimplifiedTime

getValue

getMJD

getCenturyJ2000

getScale

plusDays

minusDays

plusSeconds

minusSeconds

equals

hashCode

toString

toMoment