JulianDate Structure

An astronomical Julian Date, which is the number of days since noon on January 1, -4712 (4713 BC). For increased precision, this class stores the whole number part of the date as an Int32 and the seconds into the day as a Double.

Namespace: AGI.Foundation.Time
Assembly: AGI.Foundation.Core (in AGI.Foundation.Core.dll) Version: 25.1.421.0 (25.1.421.0)

Syntax

C++

Copy

public struct JulianDate : IComparable<JulianDate>, 
	IComparable, IEquatable<JulianDate>, IEquatableEpsilon<JulianDate>, 
	IConvertible

Public Structure JulianDate
	Implements IComparable(Of JulianDate), IComparable, 
	IEquatable(Of JulianDate), IEquatableEpsilon(Of JulianDate), IConvertible

public value class JulianDate : IComparable<JulianDate>, 
	IComparable, IEquatable<JulianDate>, IEquatableEpsilon<JulianDate>, 
	IConvertible

[<SealedAttribute>]
type JulianDate =  
    struct
        interface IComparable<JulianDate>
        interface IComparable
        interface IEquatable<JulianDate>
        interface IEquatableEpsilon<JulianDate>
        interface IConvertible
    end

The JulianDate type exposes the following members.

Constructors

	Name	Description
	JulianDate(DateTime)	Initializes a JulianDate from a DateTime. The time standard will be CoordinatedUniversalTime (UTC).
	JulianDate(Double)	Initializes a JulianDate from a double expressing the complete astronomical Julian Date. The time standard will be International Atomic Time (TAI).
	JulianDate(GregorianDate)	Initializes a JulianDate from a GregorianDate. The time standard will be CoordinatedUniversalTime (UTC), except when the gregorianDate represents time during a leap second. During a leap second, the JulianDate will be in the InternationalAtomicTime (TAI) standard.
	JulianDate(DateTime, TimeStandard)	Initializes a JulianDate from a DateTime and specified time standard.
	JulianDate(Double, TimeStandard)	Initializes a JulianDate from a double expressing the complete astronomical Julian Date.
	JulianDate(GregorianDate, TimeStandard)	Initializes a JulianDate from a GregorianDate where the GregorianDate is expressed in the given TimeStandard. If the date is during a leap second, the JulianDate will be expressed in InternationalAtomicTime (TAI).
	JulianDate(Int32, Double)	Initializes a JulianDate from the provided values. The values will be normalized so that the SecondsOfDay property is less than the length of a day. The time standard will be International Atomic Time (TAI).
	JulianDate(Int32, Double, TimeStandard)	Initializes a JulianDate from the provided values. The values will be normalized so that the SecondsOfDay property is less than the length of the day.

Top

Properties

	Name	Description
	Day	Gets the integer portion of the Julian Date (or astronomical Julian day number).
	MaxValue	Gets the largest possible value of JulianDate. This date is in InternationalAtomicTime and may not be representable in other time standards.
	MinValue	Gets the smallest value possible of JulianDate. This date is in InternationalAtomicTime and may not be representable in other time standards.
	Now	Gets the JulianDate that represents the current system date and time. The time standard will be CoordinatedUniversalTime (UTC).
	SecondsOfDay	Gets the number of seconds past noon on the whole-number Julian Day.
	Standard	Gets the TimeStandard that this astronomical Julian date is based upon.
	TotalDays	Gets the total number of whole and fractional days represented by this astronomical Julian date.

Top

Methods

	Name	Description
	Add	Adds a Duration to this Julian date, producing a new JulianDate.
	AddClamped	Adds a Duration to this Julian date, producing a new JulianDate. Unlike Add(Duration), this method will clamp the result to the valid range of values for JulianDate rather than throwing an exception. In most cases, Add(Duration) should be used instead.
	AddDays	Adds the specified number of days to this date and returns the new date.
	AddHours	Adds the specified number of hours to this date and returns the new date.
	AddMinutes	Adds the specified number of minutes to this date and returns the new date.
	AddSeconds	Adds the specified number of seconds to this date and returns the new date.
	CompareTo(JulianDate)	Compares this instance with another instance of the same type.
	CompareTo(Object)	Compares this instance with another instance of the same type.
	DaysDifference	Computes the number of days that have elapsed from this Julian date to the other Julian date.
	Equals(JulianDate)	Returns true if this date exactly equals another date. To be considered equal, Day and SecondsOfDay must be identical when converted to a common time standard. It is highly recommended that you use EqualsEpsilon(JulianDate, Double) or IsIdentical(JulianDate) instead of this method.
	Equals(Object)	Returns true if this date exactly equals another date. To be considered equal, Day and SecondsOfDay must be identical when converted to a common time standard. It is highly recommended that you use EqualsEpsilon(JulianDate, Double) or IsIdentical(JulianDate) instead of this method. (Overrides ValueType.Equals(Object).)
	EqualsEpsilon	Returns true if this date is within epsilon seconds of the specified date. That is, in order for the dates to be considered equal (and for this function to return true), the absolute value of the difference between them, in seconds, must be less than or equal to epsilon.
	GetCenterOfWindow	Divides time into windows, each of length windowLength seconds, with the first window centered on referenceEpoch. Then, identifies which window contains date and returns the date that is at the center of that window. This is helpful for computing a discrete value for a range of Julian dates.
	GetHashCode	Returns a hash code for this instance, which is suitable for use in hashing algorithms and data structures like a hash table. (Overrides ValueType.GetHashCode().)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	IsIdentical	Returns true if this date is identical to another date. Unlike Equals(JulianDate), this method will consider two dates with different time standards to be different, even if the dates represent the same moment when expressed in the same time standard.
	JulianDateToYearFraction	Computes the fraction of the year corresponding to the given Julian date.
	MinutesDifference	Computes the number of minutes that have elapsed from this Julian date to the other Julian date.
	SecondsDifference	Computes the number of seconds that have elapsed from this Julian date to the other Julian date.
	Subtract(Duration)	Subtracts a Duration from this Julian date, producing a new JulianDate.
	Subtract(JulianDate)	Subtracts another Julian date from this Julian date.
	SubtractDays	Subtracts the specified number of days from this date and returns the new date.
	SubtractHours	Subtracts the specified number of hours from this date and returns the new date.
	SubtractMinutes	Subtracts the specified number of minutes from this date and returns the new date.
	SubtractSeconds	Subtracts the specified number of seconds to this date and returns the new date.
	ToDateTime()	Converts this JulianDate to a DateTime with a default time standard of CoordinatedUniversalTime (UTC).
	ToDateTime(TimeStandard)	Converts this JulianDate to a DateTime expressed in the specified time standard.
	ToGregorianDate()	Converts this JulianDate to a GregorianDate with a default time standard of CoordinatedUniversalTime (UTC).
	ToGregorianDate(TimeStandard)	Converts this JulianDate to a GregorianDate expressed in the specified time standard.
	ToString	Returns the value of this JulianDate in the standard format. (Overrides ValueType.ToString().)
	ToTimeStandard	Converts this JulianDate to the specified time standard.
	TryConvertTimeStandard	Try to convert this JulianDate to the specified TimeStandard, if the specified TimeStandard is capable of representing this time.

Top

Operators

	Name	Description
	Addition	Adds a Duration to a JulianDate, producing a new JulianDate.
	Equality	Returns true if two dates are exactly equal. To be considered equal, Day and SecondsOfDay must be identical when converted to a common time standard. It is highly recommended that you use EqualsEpsilon(JulianDate, Double) or IsIdentical(JulianDate) instead of this method.
	GreaterThan	Returns true if left occurs after right.
	GreaterThanOrEqual	Returns true if left occurs after or at the same time as right.
	Inequality	Returns true if two dates are NOT exactly equal. To be considered equal, Day and SecondsOfDay must be identical when converted to a common time standard. It is highly recommended that you use EqualsEpsilon(JulianDate, Double) or IsIdentical(JulianDate) instead of this method.
	LessThan	Returns true if left occurs before right.
	LessThanOrEqual	Returns true if left occurs before or at the same time as right.
	Subtraction(JulianDate, Duration)	Subtracts a Duration from a Julian date, producing a new JulianDate.
	Subtraction(JulianDate, JulianDate)	Subtracts a Julian date from another Julian date, producing a Duration.

Top

Remarks

This type assumes that days always have SecondsPerDay (86400.0) seconds. When using a JulianDate with the CoordinatedUniversalTime (UTC) time standard, a day with a leap second actually has 86401.0 seconds. The end result is that JulianDate cannot represent the moment of a leap second in the UTC time standard. However, it CAN represent the moment of a leap second in InternationalAtomicTime (TAI). Also, subtracting two UTC dates that are on opposite sides of a leap second will correctly take the leap second into account.

Reference

AGI.Foundation.Time Namespace