First of Two 2012 Lunar Eclipses Happens June 4 as Partial Eclipse

Summary: The first of two 2012 lunar eclipses happens Monday, June 4, as a partial eclipse with visibility over five continents

Earth visibility chart and eclipse data for partial lunar eclipse of Monday, June 4, 2012: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment, Eclipse Predictions by Fred Espenak, NASA GSFC Emeritus," via NASA Eclipse Web Site

The first of two 2012 lunar eclipses happens Monday, June 4, as a partial eclipse that favors the Pacific Ocean and its five bordering continents.

Their advantageous locations in the South West Pacific Ocean allow observers in eastern Australia, New Zealand and most of New Guinea to enjoy viewing the entire ecliptic event.

All eclipse visibility is available to the United States’ two non-contiguous states, Alaska and Hawaii. South central Alaska, including the state’s capital of Anchorage, and the Aleutian Islands fall within the region of entire ecliptic visibility. Desirably located in the central Pacific Ocean, the Hawaiian archipelago experiences complete viewing of the June 2012 lunar eclipse.

Eleven of the United States’ 16 territories are found in the Pacific Ocean. All eclipse visibility is afforded to all 11: American Samoa, Baker Island, Guam, Howland Island, Jarvis Island, Johnston Atoll, Kingman Reef, Midway Islands, the Northern Marianas Islands, Palmyra Atoll and Wake Island.

On the NASA Eclipse Web Site, retired astrophysicist Fred Espenak, known as “Mr. Eclipse,” notes the influence of moonrise and moonset upon eclipse visibility. The eclipse’s start before moonrise prevents observers in eastern Asia from viewing the beginning. Moonset before the eclipse’s end affects the Americas. Moonset before the event starts places New England and eastern Canada within the region of non-visibility. Observers in western Canada and the western continental United States are able to view the event, up to sometime after mid-eclipse, when moonset occurs.

Africa and Europe are excluded from the June 2012 eclipse’s visibility regions. Central and western Asia also fall within the non-visibility area.

The first of two 2012 lunar eclipses begins Monday, June 4, with the lunar surface’s contact with Earth’s lighter, outer penumbral shadow. First contact with the penumbra occurs at 8:48:09 Universal Time (4:48 a.m. Eastern Daylight Time). P1 is the designator for the instant of first penumbral contact.

The partial eclipse begins with contact with Earth’s umbra at 9:59:53 UT (5:59 a.m. EDT). U1 designates the instant of entrance into the darkest, innermost part of Earth’s shadow. During the partial eclipse, part of the umbra covers a portion, but not all, of the visible lunar surface.

Greatest eclipse takes place at 11:03:13 UT (7:03 a.m. EDT). Greatest eclipse marks the instant of the closest lunar passage to the axis of Earth’s shadow.

The partial eclipse ends with last umbral contact at 12:06:30 UT (8:06 a.m. EDT). U4 designates the instant of last umbral contact.

The June 2012 lunar event ends with last penumbral contact. The penumbral eclipse ends at 13:18:17 UT (9:18 a.m. EDT). P4 is the designator for exit from the penumbra.

The June 2012 lunar eclipse has a total duration of 4 hours 30 minutes 8 seconds. The total duration represents the length of the event’s penumbral eclipse.

The event’s partial eclipse lasts for 2 hours 6 minutes 37 seconds. Partiality’s time span accounts for passage of a portion of the lunar surface through Earth’s umbra.

The June 2012 partial lunar eclipse is the first of two 2012 lunar eclipses. The year’s second ecliptic event occurs five and four-fifths months later. On Wednesday, Nov. 28, a penumbral eclipses appears as the year’s second lunar eclipse.

The June 2012 partial lunar eclipse breaks the pattern of total lunar eclipses that prevailed for almost a year. All three lunar eclipses occurring between December 2011 and December 2012 were total lunar eclipses.

The June 2012 lunar eclipse belongs to Saros Series 140. The Saros cycle links eclipses into families, known as series. A Saros cycle numbers approximately 6,585.3 days (18 years 11 days 8 hours).

The first of two 2012 lunar eclipses opens the year’s lineup of lunar eclipses, favors the Pacific Ocean with complete visibility and breaks the pattern of total lunar eclipses that endured from December 2011 to December 2012.

graphic of "orientation of the earth as viewed from the center of the moon during greatest eclipse" for partial lunar eclipse June 4, 2012: Tom Ruen (SockPuppetForTomruen at English Wikipedia), Public Domain, via Wikimedia Commons

Acknowledgment

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

Image credits:

Earth visibility chart and eclipse data for partial lunar eclipse of Monday, June 4, 2012: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment, Eclipse Predictions by Fred Espenak, NASA GSFC Emeritus," via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2012-Fig03.pdf

graphic of "orientation of the earth as viewed from the center of the moon during greatest eclipse" for partial lunar eclipse June 4, 2012: Tom Ruen (SockPuppetForTomruen at English Wikipedia), Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Lunar_eclipse_from_moon-2012Jun04.png

For further information:

Espenak, Fred. “Eclipses During 2012.” NASA Eclipse Web Site > Lunar Eclipses.
Available via NASA Eclipse Web Site https://eclipse.gsfc.nasa.gov/OH/OH2012.html

Espenak, Fred. "Figure 3 Partial Lunar Eclipse of 2012 Jun 04." NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Page > Lunar Eclipses Past and Future: Eclipses During 2012 > Eclipses During 2012: 2012 Jun 04 Partial Lunar Eclipse: Partial Lunar Eclipse of June 04.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/OH/OHfigures/OH2012-Fig03.pdf

Espenak, Fred. “Greatest Eclipse.” NASA Eclipse Web Site > Solar Eclipses > Glossary of Solar Eclipse Terms.
Available via NASA Eclipse Web Site https://eclipse.gsfc.nasa.gov/SEhelp/SEglossary.html

Espenak, Fred. “Lunar Eclipses: 2011-2020.” NASA Eclipse Web Site > Lunar Eclipses.
Available via NASA Eclipse Web Site https://eclipse.gsfc.nasa.gov/LEdecade/LEdecade2011.html

“June 4, 2012 -- Partial Lunar Eclipse.” Time And Date > Sun & Moon > Eclipses.
Available via Time And Date @ https://www.timeanddate.com/eclipse/lunar/2012-june-4

Marriner, Derdriu. "June 4, 2012, Partial Lunar Eclipse Belongs to Saros Series 140." Earth and Space News. Wednesday, May 23, 2012.
Available @ https://earth-and-space-news.blogspot.com/2012/05/june-4-2012-partial-lunar-eclipse.html

Marriner, Derdriu. “Second of Two 2011 Total Lunar Eclipses Happens Saturday, Dec. 10.” Earth and Space News. Wednesday, Dec. 7, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/12/second-of-two-2011-total-lunar-eclipses.html