May 2018 Lunar Perigee Happened Thursday, May 17, During Eta Aquarids

Summary: May 2018 lunar perigee happened Thursday, May 17, at the month’s closest Earth-moon center-to-center distance of 363,777 kilometers.

waxing crescent moon Thursday, May 17, at 21:00 UTC (5 p.m. EDT), six minutes before May’s lunar perigee: Ernie Wright (USRA lead visualizer), John Keller (NASA GSFC scientist), Noah Petro (NASA GSFC scientist) and David Ladd (USRA producer), via NASA/Goddard Space Flight Center Scientific Visualization Studio

May 2018 lunar perigee happened Thursday, May 17, during the Eta Aquarid meteor shower, at the month’s closest Earth-moon center-to-center distance of 363,777 kilometers (226,040.548 miles), at 21:06 Coordinated Universal Time/Greenwich Mean Time (5:06 p.m. Eastern Daylight Time).

May 2018’s lunar perigee of 363,777 kilometers is 4,936 kilometers closer to Earth than April 2018’s lunar perigee of 368,713. April’s lunar perigee happened Friday, April 20, at 14:44 UTC/GMT (10:44 a.m. EDT).

May 2018’s lunar perigee of 363,777 kilometers is 4,270 kilometers farther from Earth than June 2018’s lunar perigee of 359,507 kilometers. June’s lunar perigee occurs Thursday, June 14, at 23:55 UTC/GMT (7:55 p.m. EDT).

Each month the center-to-center distance between Earth and Earth’s moon logs two maximums. Perigee (Ancient Greek: περί, perí, “near” + γῆ, gê, “Earth”) designates the closest center-to-center distance between moon and Earth. The opposite maximum is apogee (Ancient Greek: ἀπόγειον, apógeion, “away from Earth” + ἀπό, apó, “away” + γῆ, gê, “Earth”), which references the farthest center-to-center distance between moon and Earth.

Astronomers also note the minimum and maximum values for each year’s perigee and apogee. Maximum perigee represents the farthest center-to-center distance in the closeness range. Minimum perigee indicates the closest center-to-center distance in the closeness range. Closest perigee for the year is known as proxigee.

Maximum perigee, or farthest perigee, for 2018 happens Wednesday, Oct. 31, at 20:05 UTC/GMT (4:05 p.m. EDT) and spans an Earth-moon center-to-center distance of 370,201 kilometers. The year’s maximum perigee of 370,201 kilometers is 6,424 kilometers farther from Earth than May’s lunar perigee of 363,777 kilometers.

The moon obtained 2018’s minimum perigee, or closest perigee, Monday, Jan. 1, at 21:54 UTC/GMT (4:54 p.m. Eastern Standard Time). The minimum perigee for 2018 is 356,566 kilometers. The year’s minimum perigee of 356,566 kilometers is 7,211 kilometers closer to Earth than May’s lunar perigee of 363,777 kilometers.

The moon phase at May 2018’s lunar perigee was waxing crescent, with about 6 percent visibility of the lunar surface for Earth’s observers. Waxing crescent numbers second in the moon’s eight-phase cycle. The waning crescent phase follows the darkened new moon and transitions to the first quarter phase of half illumination.

April 2018’s lunar perigee took place also with a waxing crescent moon. A new moon hosts June 2018’s lunar perigee. The year’s minimum, or closest, perigee, which happened in January, occurred during the fifth phase’s full moon. The year’s maximum, or farthest, perigee, expected in October, coincides with the seventh phase’s last quarter moon.

May 2018’s perigeic waxing crescent moon balanced the apogeic waning gibbous moon Sunday, May 6, that offered a troublesome glare for Earth observers watching for Eta Aquarid shooting stars. Apogee's largely darkened moon set in the evening, long before the best hours for meteor shower viewing.

The Eta Aquarids’ annual display of showering meteors takes place from mid-late April to mid-late May, from around April 19 to around May 28. Peak viewing, which usually happens around May 5 or 6, tends to promise especially good hourly rates. Interference with easy viewability comes from cloud cover or from a bright, day-setting moon, such as May 6’s waning gibbous.

The Eta Aquarid meteor shower is named for Eta Aquarii (η Aqr, η Aquarii) in Aquarius the Cup Bearer, or Water Carrier, constellation. The path of Eta Aquarid meteors appears to trace back in the night sky to a point near Eta Aquarii. The point of origin, known as the meteor shower’s radiant, is only a visual perception.

In reality, the Eta Aquarid meteor shower originates in debris from Halley’s Comet. The short-period comet, with an orbital period of 74 to 79 years, is also associated with another meteor shower. The Orionids shower Earth between September and November, with peak activity in late October.

The takeaway for May 2018 lunar perigee is that the month’s closest Earth-moon center-to-center distance happened Thursday, May 17, while Eta Aquarid meteors still showered Earth’s night skies.

Eta Aquarid meteor shower shares Earth's skyscape with May 2018's nearest moon: EarthSky @EarthSky, via Facebook May 4, 2014

Acknowledgment

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

Image credits:

waxing crescent moon Thursday, May 17, at 21:00 UTC (5 p.m. EDT), six minutes before May’s lunar perigee: Ernie Wright (USRA lead visualizer), John Keller (NASA GSFC scientist), Noah Petro (NASA GSFC scientist) and David Ladd (USRA producer), via NASA/Goddard Space Flight Center Scientific Visualization Studio @ https://svs.gsfc.nasa.gov/4604

Eta Aquarid meteor shower shares Earth's skyscape with May 2018's nearest moon: EarthSky @EarthSky, via Facebook May 4, 2014, @ https://www.facebook.com/EarthSky/photos/a.61619521852.81951.36709031852/10151984615951853/

For further information:

EarthSky @EarthSky. "Get up before dawn and look for meteors. Eta Aquarids are at their peak!  The radiant point of Eta Aquarid meteor shower is in the constellation Aquarius, in the southeast before dawn, as seen from mid-northern latitudes." Facebook. May 4, 2014.
Available @ https://www.facebook.com/EarthSky/photos/a.61619521852.81951.36709031852/10151984615951853/

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

Espenak, Fred. “2018 Calendar of Astronomical Events Greenwich Mean Time.” Astro Pixels > Ephemeris.
Available @ http://astropixels.com/ephemeris/astrocal/astrocal2018gmt.html

Marriner, Derdriu. “February 2018 Lunar Perigee Is Tuesday, Feb. 27, at 363,938 Kilometers.” Earth and Space News. Wednesday, Feb. 21, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/02/february-2018-lunar-perigee-is-tuesday.html

Marriner, Derdriu. “March 2018 Lunar Apogee Is Sunday, March 11, at 404,682 Kilometers.” Wednesday, March 7, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/03/march-2018-lunar-apogee-is-sunday-march.html

Marriner, Derdriu. “May 2018 Lunar Apogee Happens Sunday, May 6, During Eta Aquarids.” Earth and Space News. Wednesday, May 2, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/05/may-2018-lunar-apogee-happens-sunday.html

McClure, Bruce. “Close and Far Moons in 2018.” EarthSky > Astronomy Essentials. Jan. 15, 2018.
Available @ http://earthsky.org/astronomy-essentials/close-and-far-moons

“Moon Phases May 2018.” Calendar-12.com > Moon Calendar > 2018.
Available @ https://www.calendar-12.com/moon_calendar/2018/may

Wright, Ernie. “Moon Phase and Libration, 2018.” NASA Scientific Visualization Studio/Planets and Moons.
Available @ https://svs.gsfc.nasa.gov/4604

March 2018 Lunar Apogee Is Sunday, March 11, at 404,682 Kilometers

Summary: March 2018 lunar apogee is Sunday, March 11, at 404,682 kilometers, the month’s farthest center-to-center distance between moon and Earth.

waning crescent moon at 09:00 UTC (5 a.m. EDT), 13 minutes before March’s lunar apogee: Ernie Wright (USRA lead visualizer), John Keller (NASA GSFC scientist), Noah Petro (NASA GSFC scientist) and David Ladd (USRA producer), via NASA/Goddard Space Flight Center Scientific Visualization Studio

March 2018 lunar apogee, logging the month’s farthest center-to-center distance between moon and Earth, is Sunday, March 11, at 404,682 kilometers (almost 251,458 miles), at 09:13 Greenwich Mean Time/Coordinated Universal Time (5:13 a.m. Eastern Daylight Time).

The moon phase at March's apogee is waning crescent, the last of the eight-phase lunar cycle. As viewed from Earth, the lunar surface of the 23.93 day-old-moon displays approximately 32 percent illumination. In the waning crescent phase, illumination covers less than 50 percent of the lunar disc.

March 2018’s lunar apogee of 404,682 kilometers has a center-to-center distance that is 1,019 kilometers closer than February 2018’s lunar apogee of 405,701 kilometers. February’s lunar apogee happened Sunday, Feb. 11, at 14:16 UTC (9:16 Eastern Standard Time).

March 2018’s lunar apogee of 404,682 kilometers has a center-to-center distance that is 537 kilometers farther than April 2018’s lunar apogee of 404,145 kilometers. April logs lunar apogee Sunday, April 8, at 05:32 UTC (1:32 a.m. EDT). April 2018’s lunar apogee obtains 2018’s minimum, or closest, apogee value.

Astronomers note monthly extremes in the center-to-center distance between moon and Earth. Apogee (Ancient Greek: ἀπόγειον, apógeion, “away from Earth” + ἀπό, apó, “away” + γῆ, gê, “Earth”) represents the farthest center-to-center distance. Perigee (Ancient Greek: περί, perí, “near” + γῆ, gê, “Earth”) indicates the closest center-to-center distance between moon and Earth.

March 2018 lunar perigee, or closest center-to-center distance between moon and Earth, happens Monday, March 26, at 17:17 UTC (1:17 p.m. EDT). March’s perigee logs 369,104 kilometers.

March 2018’s lunar perigee of 369,104 kilometers is 5,166 kilometers farther than February 2018’s lunar perigee of 363,938 kilometers. February’s perigee occurred Tuesday, Feb. 27, at 14:48 UTC (9:48 a.m. EST).

March 2018’s lunar perigee of 369,104 kilometers is 391 kilometers farther than April 2018’s lunar perigee of 368,713 kilometers. April’s perigee takes place Friday, April 20, at 14:44 UTC (10:44 a.m. EDT).

The greatest range between apogee and perigee for the three successive 2018 months of February, March and April takes place in February. February’s lunar apogee of 405,701 kilometers was 41,763 kilometers farther than February’s lunar perigee of 363,938 kilometers.

Second place among the trio for apogee-perigee range goes to March. March 2018’s lunar apogee of 404,682 kilometers is 35,578 kilometers farther than March’s lunar perigee of 369,104 kilometers.

Of the three months, April’s apogee-perigee range is the smallest. April’s lunar apogee of 404,145 will be 35,432 kilometers farther than April’s lunar perigee of 368,713 kilometers.

Astronomers also attend to the year’s minimum and maximum values for apogee and perigee. Maximum apogee marks the year’s farthest center-to-center distance. Minimum apogee represents the closest point among the year’s far distances.

January 2018’s distance of 406,461 kilometers claims the year’s maximum, or farthest, apogee. January’s lunar apogee happened Monday, Jan. 15, at 02:10 UTC (Sunday, Jan. 14, at 9:10 EST). April 8’s center-to-center distance of 404,145 kilometers qualifies for minimum, or closest, apogee. The year’s maximum apogee of 406,461 kilometers is 2,316 kilometers farther than the year’s minimum apogee of 404,145 kilometers.

March 2018’s lunar apogee of 404,682 kilometers is 537 kilometers farther than the year’s minimum, or closest, apogee of 404,145 kilometers. March 2018’s lunar apogee of 404,682 kilometers is 1,779 kilometers closer than the year’s maximum, or farthest, apogee of 406,461 kilometers.

Maximum perigee signifies the farthest point in the year’s closest distances. Minimum perigee signals the closest of the year’s close distances. The year’s minimum perigee is also known as proxigee.

October 2018’s distance of 370,201 kilometers claims the year’s maximum, or farthest, perigee. October’s lunar perigee takes place Wednesday, Oct. 31, at 20:05 UTC (4:05 p.m. EDT). January 2018’s perigee of 356,566 kilometers represents 2018’s proxigee. The year’s maximum, or farthest, perigee of 370,201 kilometers is 13,635 kilometers farther than the year’s minimum perigee of 356,566 kilometers.

March 2018’s lunar perigee of 369,104 kilometers is 1,097 kilometers closer than the year’s maximum, or farthest, perigee of 370,201 kilometers. March 2018’s lunar perigee of 369,104 kilometers is 12,538 kilometers farther than the year’s proxigee, or minimum perigee, of 356,566 kilometers.

March 2018’s apogee and perigee take place in the year’s second blue moon month. The year’s first blue moon happened at the end of January. A blue moon month features two full moons within the same month. January’s first full moon happened Tuesday, Jan. 2, at 02:24 UTC (Monday, Jan. 1, at 9:24 p.m. EST). January’s blue moon closed the month with an appearance Wednesday, Jan. 31, at 13:27 UTC (8:27 a.m. EST).

March’s first full moon appears Friday March 2, at 00:51 UTC (Thursday, March 1, at 7:51 p.m. EST). March’s apogee is obtained 9 days 8 hours 22 minutes after the month’s first full moon.

March logs lunar perigee 4 days 19 hours 20 minutes prior to the month’s blue, or second full, moon. March’s blue moon appears Saturday, March 31, at 12:37 UTC (8:37 a.m. EDT).

The takeaway for March 2018 lunar apogee, happening Sunday, March 11, at 404,682 kilometers, is that the month’s milestones of apogee, or farthest distance, and of perigee, or closest distance, succeed and precede, respectively, March’s first and second full moons.

waxing gibbous moon at 17:00 UTC (1 p.m. EDT), 17 minutes before March’s lunar perigee: Ernie Wright (USRA lead visualizer), John Keller (NASA GSFC scientist), Noah Petro (NASA GSFC scientist) and David Ladd (USRA producer), via NASA/Goddard Space Flight Center Scientific Visualization Studio

Acknowledgment

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

Image credits:

waning crescent moon at 09:00 UTC (5 a.m. EDT), 13 minutes before March’s lunar apogee: Ernie Wright (USRA lead visualizer), John Keller (NASA GSFC scientist), Noah Petro (NASA GSFC scientist) and David Ladd (USRA producer), via NASA/Goddard Space Flight Center Scientific Visualization Studio @ https://svs.gsfc.nasa.gov/4604

waxing gibbous moon at 17:00 UTC (1 p.m. EDT), 17 minutes before March’s lunar perigee: Ernie Wright (USRA lead visualizer), John Keller (NASA GSFC scientist), Noah Petro (NASA GSFC scientist) and David Ladd (USRA producer), via NASA/Goddard Space Flight Center Scientific Visualization Studio @ https://svs.gsfc.nasa.gov/4604

For further information:

Espenak, Fred. “2018 Calendar of Astronomical Events Greenwich Mean Time.” Astro Pixels > Ephemeris.
Available @ http://astropixels.com/ephemeris/astrocal/astrocal2018gmt.html

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

Espenak, Fred. “Phases of the Moon: 2001 to 2100 Universal Time.” Astro Pixels > Ephemeris > Moon.
Available @ http://www.astropixels.com/ephemeris/phasescat/phases2001.html

Gaherty, Geoff. “Equinox Explained: Why Earth’s Seasons Will Change on Sunday.” Space.com > Skywatchng. Sept. 18, 2013.
Available @ https://www.space.com/22852-fall-equinox-earth-seasons-explained.html

Marriner, Derdriu. “2017 Spring Equinox Happens Monday, March 20, in Northern Hemisphere.” Earth and Space News. Wednesday, March 15, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/03/2017-spring-equinox-happens-monday.html

Marriner, Derdriu. “American Samoa Has Autumn Equinox While United States Has Spring Equinox.” Earth and Space News. Wednesday, March 1, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/03/american-samoa-has-autumn-equinox-while.html

Marriner, Derdriu. “First March Full Moon Friday, March 2, Opens Second 2018 Blue Moon Month.” Earth and Space News. Wednesday, Feb. 28, 2018.
Available @ https://earth-and-space-news.blogspot.com/2018/02/first-march-full-moon-friday-march-2.html

Marriner, Derdriu. “First Point of Aries for Spring Equinox Actually Happens in Pisces.” Earth and Space News. Wednesday, March 8, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/03/first-point-of-aries-for-spring-equinox.html

McClure, Bruce. “Equinox Sun Rises Due East, Sets Due West.” EarthSky > Tonight. March 20, 2018.
Available @ http://earthsky.org/tonight/equinox-sun-rises-due-east-and-sets-due-west

“Moon Phases March 2018.” Calendar-12.com > Moon Calendar > 2018.
Available @ https://www.calendar-12.com/moon_calendar/2018/march

“Sunday, March 11, 2018.” Moongiant > Phase.
Available @ http://www.moongiant.com/phase/3/11/2018