TOC  | Last Section | Next Section | First Section

leap.sec

Dates when leap seconds are inserted into Coordinated Universal Time

Overview

Leap seconds are "extra" seconds inserted (or removed) into Coordinated Universal Time (UTC) to keep UTC in synch with Universal Time (UT = UT1) which, in turn, is defined by the rotation of the Earth. Certain guidelines define when leap seconds will occur: In the US, leap second announcements circulate from the U.S. Naval Observatory.

The leap.sec file simply lists the date the leap seconds was inserted starting with June 30, 1982. The file is ASCII.

Example 

LEAP SECOND TABLE    CREATED 87/12/15   UPDATED  97/07/02
(1X,I7)                      9999999.0 DUMMY EOF  
 2445151.0                   !JUNE 30, 1982 LEAP SEC INCREMENT
 2445516.0                   !JUNE 30, 1983 LEAP SEC INCREMENT
 2446247.0                   !JUNE 30, 1985 LEAP SEC INCREMENT
 2447161.0                   !DEC  31, 1987 LEAP SEC INCREMENT
 2447892.0                   !DEC  31, 1989 LEAP SEC INCREMENT
 2448257.0                   !DEC  31, 1990 LEAP SEC INCREMENT
 2448804.0                   !JUN  30, 1992 LEAP SEC INCREMENT
 2449169.0                   !JUN  30, 1993 LEAP SEC INCREMENT 
 2449534.0                   !JUN  30, 1994 LEAP SEC INCREMENT
 2450083.0                   !DEC  31, 1995 LEAP SEC INCREMEMT
 2450630.0                   !JUN  30, 1997 LEAP SEC INCREMEMT
 9999999.0                   !DUMMY LEAP SECOND RECORD
where:

Line 1 is a descriptive header.

Line 2 gives the format for reading the file.

Thereafter, each line has the Julian day number for the date each leap second was inserted.

The last record designates the end of the file. 

 TOC  | Last Section | Next Section | First Section
leap.html
October 10, 2000
Steve Hilla