2017 Lunar Apogee Maximum Happens Dec. 19 at 406,605 Kilometers

Summary: The 2017 lunar apogee maximum, which the year’s highest monthly apogee, happens Tuesday, Dec. 19, at 406,605 kilometers (252,652.634 miles).

map of Earth at instant of 2017 lunar apogee maximum, Tuesday, Dec. 19, at 1:27 UTC (8:27 p.m. EST): John Walker/Earth and Moon Viewer, Public Domain, via Fourmilab Switzerland

The 2017 lunar apogee maximum, which marks the highest of the year’s monthly farthest center-to-center distances from Earth to its moon, happens Tuesday, Dec. 19, at 406,605 kilometers (252,652.634 miles).

The 2017 lunar apogee maximum of 406,605 kilometers is 473 kilometers greater than the previous month’s lunar apogee maximum of 406,132 kilometers (252,358.725 miles). November 2017’s lunar apogee maximum happens Tuesday, Nov. 21, at 18:52 UTC (1:52 p.m. EST).

The 2017 lunar apogee maximum of 406,605 kilometers is 144 kilometers greater than the next month’s lunar apogee maximum of 406,461 kilometers (252,563.156 miles). January 2018’s lunar apogee maximum happens Monday, Jan. 15, at 2:10 UTC (9:10 p.m. EST, Sunday, Jan. 14). January 2018’s lunar apogee maximum qualifies both as the lunar apogee maximum for the month of January as well as for year 2018.

Retired NASA astrophysicist Fred Espenak notes the extreme lunar apogee maximum for the 21st century (Jan. 1, 2001, to Dec. 31, 2100) as occurring Monday, Dec. 12, 2061, at 7:25 UTC (2:25 a.m. EST). The 21st century’s extreme lunar apogee maximum measures a center-to-center orbital distance of 406,709 kilometers (252,717.256 miles) between the moon and its parent planet, Earth. The 2017 lunar apogee maximum of 406,605 kilometers is 104 kilometers less than the 21st century’s extreme lunar apogee maximum of 406,709 kilometers.

The moon’s orbit around Earth displays monthly extremes of closest points, known as apogee, and of farthest points, known as perigee. The somewhat elliptical shape of the lunar orbit accounts for inconsistent distances, measured from Earth’s center to moon’s center, during the moon’s monthly revolution around Earth.

According to the world’s official time standard, Coordinated Universal Time (UTC), the 2017 lunar apogee maximum takes place Tuesday, Dec. 19, at 1:27 (8:27 p.m. Eastern Standard Time, Monday, Dec. 18). Time zone conversions of Coordinated Universal Time to local times across the globe result in two dates for the astronomical event’s occurrence. Local time zones either place the 2017 lunar apogee maximum either one day earlier, on Monday, Dec. 18, or agree with the UTC’s date of Tuesday, Dec. 19. The 2017 lunar apogee maximum happens on the earlier date of Monday, Dec. 18, for time zones with a lag of two hours or more behind Coordinated Universal Time.

All states and possessions of the United States place the 2017 lunar apogee maximum on the earlier date, Monday, Dec. 18. For American Samoa, which is one of only two U.S. possessions in the Southern Hemisphere, the 2017 lunar apogee maximum happens Monday, Dec. 18, at 2:27 p.m. Samoa Standard Time (SST). American Samoa lags 11 hours behind Coordinated Universal Time and does not observe daylight savings.

Only about 64 kilometers (39.76 miles) of the central South Pacific Ocean separate American Samoa, the eastern segment of the Samoa Islands archipelago, from the western segment, the Independent State of Samoa (Malo Sa 'oloto Tuto 'atasi o Sāmoa). Yet, the two segments lie in different time zones and place the 2017 lunar apogee maximum on two different dates.

For the Independent State of Samoa (Malo Sa 'oloto Tuto 'atasi o Sāmoa), the 2017 lunar apogee maximum happens Tuesday, Dec. 19, at 3:27 p.m., according to daylight saving time (DST) in the West Samoa Time Zone (WST). Samoa’s standard time, which is 13 hours ahead of Coordinated Universal Time, is represented by the identifier UTC+13. During standard time, Samoa is 24 hours ahead of American Samoa. Samoa’s daylight saving time, which is 14 hours ahead of Coordinated Universal Time, is represented by the identifier UTC+14. During daylight saving time, Samoa is 25 hours ahead of American Samoa.

The 2017 lunar apogee maximum happens less than 19 hours (18 hours 57 minutes) after the moon’s start of a new monthly cycle. At 6:30 UTC (1:30 a.m. EST), Monday, Dec. 18, the moon transitioned from waning crescent phase to new phase.

The takeaway for the 2017 lunar apogee maximum that happens Dec. 19 at 406,605 kilometers, at 1:27 a.m. UTC (8:27 p.m. EST), is that the figure represents the farthest center-to-center distance between Earth and its moon not only for the month of December but also for the entire year 2017.

darkness of new moon, Tuesday, Dec. 19, 2017, 1:00 UTC, 27 minutes before 2017 lunar apogee maximum and 18.5 hours after moon’s start of new phase: 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 apogee maximum, Tuesday, Dec. 19, at 1:27 UTC (8:27 p.m. EST): John Walker/Earth and Moon Viewer, Public Domain, via Fourmilab Switzerland @ https://www.fourmilab.ch/cgi-bin/Earth

new moon, Tuesday, Dec. 19, 2017, 1:00 UTC, 27 minutes before 2017 lunar apogee maximum and 18.5 hours after moon’s start of new phase: 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 Tuesday, December 19, 2017 at 1:27:00 a.m.” Time And Date > Time Zones > World Clock > Event Time Announcer.
Available @ https://www.timeanddate.com/worldclock/fixedtime.html?p1=1440&iso=20171219T0127&low=4

Marriner, Derdriu. “2017 Lunar Apogee Minimum Happens Aug. 30 at 404,307 Kilometers.” Earth and Space News. Wednesday, Aug. 23, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/08/2017-lunar-apogee-minimum-happens-aug.html

Marriner, Derdriu. “2017 Lunar Perigee Maximum Happens Sept. 13 at 369,856 Kilometers.” Earth and Space News. Wednesday, Sept. 13, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/09/2017-lunar-perigee-maximum-happens-sept.html

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

“Time Changes in Apia Over the Years.” Time And Date > Time Zones > World > Samoa > Apia.
Available @ https://www.timeanddate.com/time/zone/samoa/apia

“Time Zone Abbreviations - Worldwide List.” Time And Date > Time Zones.
Available @ https://www.timeanddate.com/time/zones/

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