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Closest Full Moon of 2013 on June 23


The closest Full Moon of the year will fall on June 23, 2013. Since it's the closest Full Moon, it'll also be the year's largest Full Moon. Watch it usher in extra large spring tides along the ocean shorelines.


Enter Lunar Apogee and Lunar Perigee


Full MoonDuring the course of one month, the Moon's distance from Earth varies by about 50,000 kilometers (30,000 miles). For instance, the Moon will swing to apogee - its greatest distance for the month - on June 9, at which time the Moon will be 406,486 kilometers away. Some two weeks later, on June 23, the Moon will be at perigee - its closest point to Earth for the month - with the Moon residing at 356,991 kilometers distant.

Photo Credit: bilbord99


Full Moon Aligns With Lunar Perigee


June 23 presents the only time this year that the Full Moon will fall on the same date as lunar perigee. Additionally, this particular June 23, 2013 perigee gives us the closest perigee of the year. As a rule of thumb, the year's closest perigee happens on the day that the Full Moon and perigee coincide.


Closest Full Moons Come in Cycles of 14 Lunar Months


When will the closest Full Moon happen again? It'll happen on the 14th Full Moon after this June 23 Full Moon because closest Full Moons recur every 14 lunar (synodic) months.

A lunar month refers to the period of time between successive Full Moons, a period of 29.53059 days. An anomalistic month is the measure of time between successive perigees, a period of 27.55455 days.

Amazingly enough, 14 lunar months almost exactly equal 15 anomalistic months:


14 x 29.53059 = 413.428 days

15 x 27.55455 = 413.318 days


This time period is equal to about 1 year 1 month and 18 days. Next year, the Full Moon and perigee will realign on August 10, 2014.

Incidentally, the Full Moon on June 23, 2013 falls at 11:32 Universal Time. That's 7:32 a.m. Eastern Daylight Time, 6:32 a.m. Central Daylight Time, 5:32 a.m. Mountain Daylight Time and 4:32 a.m. Pacific Daylight Time.


Moon Closest To Earth


Year

Date

Distance

2011

March 19

356,575 km

2012

May 6

356,955 km

2013

June 23

356,991 km

2014

August 10

356,896 km

2015

September 28

356,877 km

2016

November 14

356,509 km


Looking further into the future, the perigee full moon will come closer than 356,500 kilometers for the first time in the 21st century on November 25, 2034 (356,446 km). The closest full moon of the 21st century will fall on December 6, 2052 (356,421 km).


copyright 2013 by Bruce McClure


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