# Julian date

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Related to Julian date: Julian calendar, Gregorian date
Julian Date

## Julian date

(JD) The number of days that have elapsed since noon GMT on Jan. 1 4713 bc – the Julian day number – plus the decimal fraction of the day that has elapsed since the preceding noon. The consecutive numbering of days makes the system independent of the length of month or year and the JD is thus used to calculate the frequency of occurrence or the periodicity of phenomena over long periods. The system was devised in 1582 by the French scholar Joseph Scaliger. A specific Julian date can be determined from astronomical tables of Julian day numbers: thus since March 1 1980, noon GMT, is tabulated as day number 244 4300 then March 17 1980, 6 p.m. GMT, is JD 244 4316.25 (see table). The modified Julian date (MJD) is found by subtracting 240 0000.5 from the Julian date.

## Julian date

[′jül·yən ¦dāt]
(astronomy)
The sum of the Julian day number and the fraction of a day elapsed since the previous noon.

## Julian date

A calendar notation in which the date is represented by one number. For example, the Julian date for December 11, 1942 is 2430705; while December 12, 1942 is 2430706. The Julian date is widely used with computers because it requires less programming to compare dates that are single integers. Julian numbers are also used within a single year; for example, February 1 is Julian 32.

Developed in the 16th century by Joseph Scaliger, the numbers were based on a 7,980-year cycle that began on January 1, 4713 BC and ends January 22, 3268. Contrast with "Gregorian date," which is the common calendar notation of month, day and year.
References in periodicals archive ?
Julian dates for 1974 indicate when the specified proportion of the total number of migrating hawks was attained; Julian dates for other years are rounded approximations of percentile attainment based on mean values (in parentheses [+ or -] SE) of shift in days relative to Julian dates in 1974.
c] = 0) to explain the proportion of Brant per habitat strata, as counted from aerial surveys, contained only Julian date as a response variable (Table 3).
In cooperation with the FDA, Cal-Maine immediately notified its customers and recalled specific Julian dates of shell eggs because they have the potential to be contaminated with SE.
Such as "C" equals change Julian dates by two days forward and once the pro-word "Corona" is called over the FM all know what to do.
The laser is tasked with marking human-readable and barcoded information, including Julian dates, serial numbers, supplier codes, and part number data.
Like all other producers, Rose Acre uses Julian dates but knows they are far from buyer-friendly.
Thus, from the mid-1960s until just a few years ago, programmers wrote the logic of Julian dates into every record created, in every file processed.
NuCal Foods is voluntarily recalling specific Julian dates of shell eggs produced by Hillandale Farms of Iowa and packaged by NuCal Foods because they have the potential to be contaminated with Salmonella.
The only eggs affected by this recall have plant numbers P1860 or P1663 and Julian dates as follows:
The range consists of four models, with both the NX2 and NX4 available in either continuous or intermittent configurations, and can print real-time, texts/codes, autocodes, graphic, Julian dates and the full range of barcodes, including sequential barcodes.

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