Class ilib.JulianDay
A Julian Day class. A Julian Day is a date based on the Julian Day count of time invented by Joseph Scaliger in 1583 for use with astronomical calculations. Do not confuse it with a date in the Julian calendar, which it has very little in common with. The naming is unfortunately close, and comes from history.
Depends directive: !depends julianday.js
Defined in: ilib-dyn-full.js.
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ilib.JulianDay(num)
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| Method Attributes | Method Name and Description |
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addDate(offset)
Add an offset to the current date instance.
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getDate()
Return the Julian Day expressed as a floating point number.
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Return the fractional portion of this Julian Day instance.
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getDays()
Return the integral portion of this Julian Day instance.
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setDate(num)
Set the date of this Julian Day instance.
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setDayFraction(fraction)
Set the fractional part of the Julian Day.
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setDays(days)
Set the date of this Julian Day instance.
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Class Detail
ilib.JulianDay(num)
- Parameters:
- {number} num
- the Julian Day expressed as a floating point number
Method Detail
addDate(offset)
Add an offset to the current date instance. The offset should be expressed in
terms of Julian days. That is, each integral unit represents one day of time, and
fractional part represents a fraction of a regular 24-hour day.
- Parameters:
- {number} offset
- an amount to add (or subtract) to the current result instance.
{number}
getDate()
Return the Julian Day expressed as a floating point number.
- Returns:
- {number} the Julian Day as a number
getDayFraction()
Return the fractional portion of this Julian Day instance. This portion
corresponds to the time of day for the instance.
{number}
getDays()
Return the integral portion of this Julian Day instance. This corresponds to
the number of days since the beginning of the epoch.
- Returns:
- {number} the integral portion of this Julian Day
setDate(num)
Set the date of this Julian Day instance.
- Parameters:
- {number} num
- the numeric Julian Day to set into this instance
setDayFraction(fraction)
Set the fractional part of the Julian Day. The fractional part represents
the portion of a fully day. Julian dates start at noon, and proceed until
noon of the next day. That would mean midnight is represented as a fractional
part of 0.5.
- Parameters:
- {number} fraction
- The fractional part of the Julian date
setDays(days)
Set the date of this Julian Day instance.
- Parameters:
- {number} days
- the julian date expressed as a floating point number