Insert a leap second "8:59:60" In the field report that I witnessed at the Akashi municipal astronomical hall the very moment

Based on the rotation of the earthAstronomical timeBased on atomic clocksAtomic timeIn order to eliminate the gap of 1 second a day "Leap second (leap second)"is. On July 1, 2015 (Wednesday), leap seconds will be added for the first time in about three years, and at the Akashi Municipal Astronomy Museum, where the east longitude 135 degrees meridian passes, which is the standard of Japan Standard Time, I went to the scene where "leap second" was inserted in the parent watch that controls.

Leap second insertion work | Other events | Akashi municipal astronomical science hall
http://www.am12.jp/event/other/other_h27/uruubyou_20150701.html

Arrived at Akashi Municipal Astronomical Museum.


Before the entrance, a sign indicating the position of the meridian and a type of clock used in Japan's first timepieceEntry (candlelight)There was installation.


I will get in from the entrance gate at once.


As the Tanabata is near, Tanabata decorations were suspended on the ceiling in the hall.


The insertion of leap seconds has been done irregularly since 1972 (Showa 47), this time26 th insertionAnd that. Since the deviation of the Earth's rotation time constantly changes under the influence of the tidal power, it is unknown when the next leap second insertion will occur.


When I moved to the 3rd floor with an elevator, preparation for the leap second insertion work was done steadily. It is a master clock that controls all the clocks of the Akashi Municipal Astronomical Science Museum, and there are two primary and secondary, which are normally kept under control strictly.


Opening the secret cover and looking at the control panel inside it looks like this, various buttons and switches are lining up.


A staff member who closely adjusts the time of the master clock and the display time of the PC in a comma 1 second unit.


A telephone to listen to the NTT 's timepiece was also set.


And we are ready.


The customer entered.


Before the leap second insertion work, an explanation was given about "What is leap second?" Based on the rotation cycle of the earthWorld Time (UT), Based on atomic clocksCoordinated Universal Time (UTC)Is shifted by 1 / 1000th of a second per day, and a gap of 1 second occurs in about 3 years, so in order to fill in the time difference between astronomical and atomic times, leap seconds insertion work is performed approximately once every three years It is said that it is done at the pace of.


One of the two "Cesium Atomic Clocks", which was first used as a standard for Japan Standard Time, is exhibited at the Akashi Municipal Astronomical Science Museum.


As for the insertion of leap seconds, there are pros and cons, there are disadvantages in the country where insertion timing falls into the activity time of daytime, so, for example, America wanting to abolish leap second, where trading of hundreds of millions of shares per second policy. On the other hand, Britain opposed abolition of leap seconds because it is resistant to being separated from Greenwich Mean Time, which is astronomical time, and it is a subordinate institution of the United Nations in November 2015International Telecommunications UnionA discussion will be held as to whether or not to continue leap-second implementation at the meeting of As a staff member 's opinion, "From astronomers belonging to the Astronomical Science Museum, we hope that time standards are linked to the rotation of the earth".


The parent clock of the Akashi municipal astronomical science museum is located in Koganei, TokyoNational Institute of Information and Communications Technology (NICT)It is said that we get weekly data from the atomic clock, and if the mistake is made by mistake, the clocks in Japan are not going crazy, "To protect the honor of the hotel, people who want to press leap seconds switch! The hand calls one after another from the audience seating with a cheek calling.


Here is a squad character of Akashi municipal astronomical science hallOrbital star unit Shigo sengerRed and blue appeared.


Two people who insert leap seconds are chosen by drawing ... ...


Two leaders and two were selected.


At 8:58, we first set the "leap seconds adjustment switch" on the control panel of the master clock to "+".


The leap second adjustment switch of the other parent clock is also crisp.


Then press the "push" button of the leap second at the same time.


Then the "leap second" lamp is lit. With this, one second will be "1.01 seconds" between 8:58:00 and 8:59:40, and one second will increase in 100 seconds.


As the time goes on, the parent clock shows "8:59:39" and the normal clock shows "8:59:38", which shows that a one second gap has occurred.


You can see the appearance of "8: 59: 60 seconds" as a result of 1 second gap occurred in the following movie.

At the moment when "leap second" is inserted, 8:59:60 on July 1 - YouTube


Successfully inserted leap seconds safely! Clapping turned up from the customers.


The master clock which finished the insertion work kept cutting time.


At the end of the photo shoot with customers and Shigo senger.


Before leaving, I was able to have a commemorative Hanko on "Leap Seconds Insertion Work Tour Certificate".


Immediately stamp imprint of the memorial stamp.


Flat


Some people were stamped on the paper of commemorative shooting. Please note that this Hanko can be stamped in the hall for the entire July.