Utc Leap Seconds

My amazon cloud drive account. Since then, there have been 18 leap seconds introduced, such that there is now an 18 second difference between GPS time and UTC time. Instead of reprogramming each satellite’s internal clock with every leap second added, it was decided that an easier method would be to include the current number of leap seconds in the downloaded navigational.

Last Leap Second

Unix time (also known as Epoch time, POSIX time, seconds since the Epoch, or UNIX Epoch time) is a system for describing a point in time.It is the number of seconds that have elapsed since the Unix epoch, minus leap seconds; the Unix epoch is 00:00:00 UTC on 1 January 1970 (an arbitrary date); leap seconds are ignored, with a leap second having the same Unix time as the second before it,. 4 hours ago  By 1972, the current version of the system of time known as Coordinated Universal Time (UTC) was enacted, which uses 86400 SI seconds as defined by atomic clocks, but where an extra 'leap second' adjustment is occasionally inserted to keep UTC approximately in sync with UT (UT1, more precisely). The idea is that because 86400s is a bit too. In UTC, each second is an SI second, but leap seconds are added as necessary to readjust the clock back to within.9 seconds of GMT/UT1. The GMT and UT1 time standards are defined by empirical measurements of the Earth's position and movement in the universe, and these empirical measurements cannot through any means (neither scientific theory.

Look up intercalation or embolism in Wiktionary, the free dictionary.

Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases.[1]Lunisolar calendars may require intercalations of both days and months.


Solar calendars[edit]

The solar or tropical year does not have a whole number of days (it is about 365.24 days), but a calendar year must have a whole number of days. The most common way to reconcile the two is to vary the number of days in the calendar year.

Utc Leap Seconds Calculator

In solar calendars, this is done by adding to a common year of 365 days, an extra day ('leap day' or 'intercalary day') about every four years, causing a leap year to have 366 days (Julian, Gregorian and Indian national calendars).

The Decree of Canopus, which was issued by the pharaoh Ptolemy III Euergetes of Ancient Egypt in 239 BCE, decreed a solar leap day system; an Egyptian leap year was not adopted until 25 BC, when the Roman Emperor Augustus successfully instituted a reformed Alexandrian calendar.

In the Julian calendar, as well as in the Gregorian calendar, which improved upon it, intercalation is done by adding an extra day to February in each leap year. In the Julian calendar this was done every four years. In the Gregorian, years divisible by 100 but not 400 were exempted in order to improve accuracy. Thus, 2000 was a leap year; 1700, 1800, and 1900 were not.

Epagomenal[2] days are days within a solar calendar that are outside any regular month. Usually five epagomenal days are included within every year (Egyptian, Coptic, Ethiopian, Mayan Haab' and French Republican Calendars), but a sixth epagomenal day is intercalated every four years in some (Coptic, Ethiopian and French Republican calendars).

The Bahá'í calendar includes enough epagomenal days (usually 4 or 5) before the last month (علاء, ʿalāʾ) to ensure that the following year starts on the March equinox. These are known as the Ayyám-i-Há.

Lunisolar calendars[edit]

The solar year does not have a whole number of lunar months (it is about 365/29.5 = 12.37 lunations), so a lunisolar calendar must have a variable number of months in a year. Regular years have 12 months, but embolismic years insert a 13th 'intercalary' or 'leap' or 'embolismic' month every second or third year (see blue moon). Whether to insert an intercalary month in a given year may be determined using regular cycles such as the 19-year Metonic cycle (Hebrew calendar and in the determination of Easter) or using calculations of lunar phases (Hindu lunisolar and Chinese calendars). The Buddhist calendar adds both an intercalary day and month on a usually regular cycle.

Lunar calendars[edit]

The tabular Islamic calendar and the lunar version of the Javanese calendar (Wulan) usually have 12 lunar months that alternate between 30 and 29 days every year, but an intercalary day is added to the last month of the year 11 times within a 30-year cycle. Some historians also linked the pre-Islamic practice of Nasi' to intercalation.

Leap Second Schedule

Utc Leap Seconds

The Solar Hijri calendar and the solar version of the Javanese calendar (Mangsa) are based on solar calculations and is similar to the Gregorian calendar in its structure, and hence the intercalation, with the exception that the year date starts with the Hegira and the Hindu zodiacs, respectively.[3]

Leap seconds[edit]

Utc Leap Seconds Gps

The International Earth Rotation and Reference Systems Service can insert or remove leap seconds from the last day of any month (June and December are preferred). These are sometimes described as intercalary.[4]

Other uses[edit]

ISO 8601 includes a specification for a 52/53-week year. Any year that has 53 Thursdays has 53 weeks; this extra week may be regarded as intercalary.

The xiuhpōhualli (year count) system of the Aztec calendar had five intercalary days after the eighteenth and final month, the nēmontēmi, in which the people reflect on the past year and do fasting.

See also[edit]

  • Egyptian, Coptic, and Ethiopian calendars


  1. ^Chisholm, Hugh, ed. (1911). 'Intercalary' . Encyclopædia Britannica (11th ed.). Cambridge University Press. p. 683.
  2. ^From ἐπαγόμενος, epagomenos (present participle passive of ἐπάγειν, epagein 'to bring in') + -al
  3. ^'Hijri-Shamsi Calendar'. Al Islam. Retrieved June 14, 2014.
  4. ^leap second by Merriam-Webster OnLine
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