2017 Lunar Perigee Maximum Happens Sept. 13 at 369,856 Kilometers

Summary: The 2017 lunar perigee maximum, with the moon at closest center-to-center distance to Earth, happens Sept. 13 at 369,856 kilometers (229,817.86 miles).

map of Earth at instant of 2017 lunar perigee maximum, Wednesday, Sept. 13, at 16:04 UTC (12:04 p.m. Eastern Daylight Time): John Walker/Earth and Moon Viewer, Public Domain, via Fourmilab Switzerland

The 2017 lunar perigee maximum, with the moon at the year’s closest center-to-center distance from Earth, happens Wednesday, Sept. 13, at 369,856 kilometers (229,817.864 miles).

According to the world’s official time standard, Coordinated Universal Time (UTC), the 2017 lunar perigee maximum happens Wednesday at 16:04 (12:04 p.m. Eastern Daylight Time). Earth’s time zones, which convert Coordinated Universal Time to local times, place the 2017 lunar perigee maximum either on the UTC date or one day later, on Thursday, Sept. 14. The Thursday date applies to time zones that are ahead of UTC by eight hours or more.

The highest time zone is 14 hours ahead of Coordinated Universal Time. The time zone’s 14-hour time offset is expressed by an identifier as UTC + 14.

Formerly known as Christmas Island, Kiritimati observes the world’s farthest forward time zone. Its identifier of UTC + 14 places the 2017 lunar perigee maximum 14 hours ahead of UTC’s date of Wednesday, Sept. 13 and time of 16:04. The raised coral atoll in the North Pacific Ocean’s northern Line Islands observes the 2017 lunar perigee maximum Thursday, Sept. 14, at 6:04 a.m. Line Islands Time (LINT).

The 2017 lunar perigee maximum qualifies as a double milestone. The 2017 lunar perigee maximum claims closest center-to-center for both the month of September and for the year. The yearly perigee is also referred to as proxigee.

September 2017’s perigee of 369,856 kilometers exceeds the previous month’s perigee by 3,727 kilometers. August’s perigee measured 366,129 kilometers (227,502.013 miles). According to Coordinated Universal Time, August’s perigee happened Friday, Aug. 18, at 13:14 (9:14 a.m. EDT).

September 2017’s perigee of 369,856 kilometers exceeds the following month’s perigee by 2,998 kilometers. October’s perigee will measure kilometers 366,858 (227,954.993 miles). According to Coordinated Universal Time, October’s perigee will happen Monday, Oct. 9, at 5:51 (1:51 a.m. EDT).

Yearly perigee displays a range of two extremes. The year’s lunar perigee minimum is the counterpart to the year’s lunar perigee maximum. The year’s lunar perigee maximum references the highest of the year’s monthly perigees. The year’s lunar perigee minimum represents the lowest of the year’s monthly perigees.

According to Coordinated Universal Time, the 2017 lunar perigee minimum happened Friday, May 26, at 1:23 (9:23 p.m. EDT, Thursday, May 25), at a distance of 357,210 kilometers (221,900 miles). The range between 2017’s lunar perigee maximum of 369,856 kilometers and 2017’s lunar perigee minimum of 357,210 kilometers amounts to a difference of 12,646 kilometers.

The maximum and minimum values achieved over a century’s 100-year-span present another set of extreme perigees. The 21st century, which spans Jan. 1, 2001, to Dec. 31, 2100, witnesses a difference of 13,931 kilometers between its extreme perigee maximum and minimum values.

According to Coordinated Universal Time, the 21st century achieves an extreme perigee maximum of 370,356 kilometers (230,128.549 miles). The century’s lunar perigee maximum happens Sunday, Jan. 3, 2100, at 8:57 UTC (3:57 a.m. Eastern Standard Time).

According to Coordinated Universal Time, the 21st century’s extreme perigee minimum measures a center-to-center distance of 356,425 kilometers (221,472.227 miles). The century’s lunar perigee minimum happens Friday, Dec. 6, 2052, at 8:50 UTC (3:50 a.m. EST).

The 13,931-kilometer difference between the 21st century’s extreme perigee maximum of 370,356 kilometers and extreme perigee minimum of 356,425 kilometers exceeds the 12,646-kilometer between 2017’s lunar perigee maximum of 369,856 kilometers and lunar perigee minimum of 357,210 kilometers by 1,285 kilometers. The century’s extreme perigee maximum of 370,356 kilometers outdistances 2017’s lunar perigee maximum of 369,856 kilometers by 500 kilometers. The century’s extreme perigee minimum of 356,425 kilometers brings Earth and its moon 785 kilometers closer than the 2017 lunar perigee minimum of 357,210 kilometers.

The 2017 lunar perigee maximum takes place 10 hours 22 minutes after the moon phases into its last quarter. The moon phased from waning gibbous to last quarter Wednesday, Sept. 13, at 6:26 UTC (2:26 a.m. EDT).

The takeaway for the 2017 lunar perigee maximum that happens at 16:04 UTC, Wednesday, Sept. 13, at a center-to-center distance of 369,856 kilometers, is the milestone’s double honor as maximum perigee for both the month of September and for year 2017.

last quarter moon, Wednesday, Sept. 13, 16:00 UTC, four minutes before 2017 lunar perigee maximum: Ernie Wright/Dial-A-Moon, Public Domain, via NASA/Goddard Space Flight Center (GSFC) Scientific Visualization Studio (SVS)

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

map of Earth at instant of 2017 lunar perigee maximum, Wednesday, Sept. 13, at 16:04 UTC (12:04 p.m. Eastern Daylight Time): John Walker/Earth and Moon Viewer, Public Domain, via Fourmilab Switzerland @ https://www.fourmilab.ch/cgi-bin/Earth

last quarter moon, Wednesday, Sept. 13, 16:00 UTC, four minutes before 2017 lunar perigee maximum: Ernie Wright/Dial-A-Moon, Public Domain, via NASA/Goddard Space Flight Center (GSFC) Scientific Visualization Studio (SVS) @ https://svs.gsfc.nasa.gov/4537

For further information:

Espenak, Fred. “Moon at Perigee and Apogee: 2001 to 2100 Greenwich Mean Time.” AstroPixels > Ephemeris > Moon.
Available @ http://astropixels.com/ephemeris/moon/moonperap2001.html

“Event in UTC on Wednesday, September 13, 2017 at 4:04:00 p.m.” Time And Date > Time Zones > World Clock > Event Time Announcer.
Available @ https://www.timeanddate.com/worldclock/fixedtime.html?iso=20170913T1604&p1=1440

Marriner, Derdriu. “2017 Lunar Perigee Minimum Happens May 26 at 357,210 Kilometers.” Earth and Space News. Wednesday, May 24, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/05/2017-lunar-perigee-minimum-happens-may.html

Wright, Ernie. “Lunar Eclipses and the Moon’s Orbit.” NASA Scientific Visualization Studio. April 10, 2014.
Available @ https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=4158

Wright, Ernie. “Moon Phase and Libration, 2013.” NASA Scientific Visualization Studios. Nov. 20, 2012.
Available @ http://svs.gsfc.nasa.gov/vis/a000000/a004000/a004000/