Earth Partially Shades the Moon on June 4

Photo: Tom Ruen, from Wikipedia, December 2011 lunar eclipse near sunrise, from Minneapolis, MNEclipses tend to come in pairs, one solar and one lunar, about two weeks apart. The much-touted “annular” eclipse on May 20 is now followed by a partial lunar eclipse on Monday, June 4. This eclipse is visible in part, weather permitting, throughout North America except for far northeastern Canada and far northern Alaska. It is visible in its entirety from Hawaii, New Zealand, the eastern 2/3rds of Australia, Antarctica and the South Pacific.

Eclipse image here is from the Dec. 10, 2011 eclipse photographed by Tom Ruen.

This is similar to the eclipse on 4 June, except that the eclipsed area will be closer to the bottom as opposed to the top here. Actually, for most observers looking to the southwestern sky, the darkened portion will be to the lower left.

There are many other sources of information, so I will give you just the basics and if you need more, I’ve posted links to good sites below. On the NASA map below (click to enlarge), North American locations East (right) of the “P1” line will see essentially none of the eclipse. Observers West (left) of the “U1” line will see at least a portion of the partial eclipse before moonset. Those observers West (left) of the “U4” line will see all of the partial eclipse, weather permitting. The “P1” and “P4” lines represent the beginning and ending, respectively, of the “penumbral” portion of the eclipse, which is really of interest only to diehard eclipse afficianados.

(Map courtesy of Fred Espenak, NASA/GSFC)

The greatest extent of this eclipse (mid-eclipse), when the Earth’s darker umbral shadow covers about 37 percent of the Moon’s diameter, is at 11:03 Universal Time. This is about 7:03 a.m. EDT, 6:03 a.m. CDT, 5:03 MDT & 4:03 a.m. PDT on June 4. What this means that the maximum point of the eclipse occurs after sunrise (and unfortunately after moonset) for the eastern half of the Continent. The partial phase of the eclipse (when the first tiny “bite” is taken out of the Moon — the same thing that anciented feared was a dragon devouring the Moon — starts about an hour before in each time zone.

For observers along a line running roughly from New Orleans to Saskatoon will experience the maximum (again, only about 37%) at moonset. The view will get progressively better for observers farther West. All of the better (umbral phases, hereinafter referred to as “partial” eclipse) part of the eclipse will be visible before moonset for viewers west of a line running roughly from El Paso to Spokane, across the coastal areas of British Coloumbia and the southern half of Alaska. The partial phase begins about an hour and 3 minutes before this, and ends about and hour and 3 minutes after this.

4 June 2012 Lunar Eclipse Map

Click to Enlarge — 4 June 2012 Lunar Eclipse Map

Unlike a solar eclipse, observing a lunar eclipse is completely safe. Just go out and look at the Moon. You can safely observe with binoculars and telescopes, too, without any special filters.

Lunar eclipses occur when the Moon passes “behind” the Earth and through its shadow cast by the Sun. If the Moon orbitted in exactly the same plane as the Earth’s orbit around the Sun, we would have a solar eclipse and a lunar eclipse every lunar orbit (a “synodic” month of about 29.5 days). However, the plane of the Moon’s orbit is tilted slightly from that of the Earth, meaning that they cross in only two places. Thus eclipses occur only when the Sun, Earth and Moon are located along a straight line, and when either the Sun or Moon appear in the direction of a crossing point (called a “node” of the orbit). Nevertheless, there are typically 3-5 eclipses of some sort (lunar or solar, partial or total) visible from various locations on Earth every year.

The next lunar eclipse of any significance visible from North America occurs on April 15, 2014 (a total eclipse).

For more information on the June 4 eclipse, check out this article on EarthSky: “Lunar eclipse: Americas before sunrise, Asia after sunset June 4

You may also want to check out this NASA page: “Partial Eclipse of the Strawberry Moon

and the NASA eclipse page for the June 4 eclipse (and mroe): “Eclipses during 2012

Fred Espenak (“Mr. Eclipse”) offers tips on “How to Photograph a Lunar Eclipse

And if you have a Facebook account and get a good photo, please share it on the EarthSky Facebook!

Now, there also is a much more important — or at least rare — event coming up on June 5 — a transit of Venus across the face of the Sun! Click here: Transit of Venus


About Starman

Cosmic Awareness Facilitator. Astronomy, space, physics, science, planets, cosmology, reason, logic, clouds, sky phenomena, the environment, dogs and other animals, and other interesting stuff.
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One Response to Earth Partially Shades the Moon on June 4

  1. Pingback: This is your Last Chance to see a Venus Transit! « Starman's Meanderings

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