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Supermoon – and slight penumbral eclipse – for full moon on May 24-25

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Tonight is May 24, 2013

Moon Phase Courtesy U.S. Naval Observatory

Three planets close together in west this evening!

In 2013, the May full moon presents the third full moon after the March equinox. In North America we often call this particular full moon the Flower Moon, Rose Moon or Strawberry Moon. That star by tonight’s full moon is Antares, the brightest star in the constellation Scorpius the Scorpion. Plus the moon is one day away from lunar perigee – the moon’s closest point to Earth for this month. By a newly coined popular definition, that makes this May 24-25 full moon a supermoon. And the moon will undergo an extremely minor penumbral lunar eclipse tonight. With a penumbral eclipse magnitude of 0.0158, just 0.5 arc-minutes of the moon’s southern limb will pass into Earth’s pale penumbral shadow. It’s such a shallow eclipse that it’ll be mainly of academic interest and very difficult to detect. For more about the May 2013 lunar eclipse, click here.

What will most of us actually see tonight? Nothing unusual. Just the same wonderful full moon we see every month. Enjoy it.

What is a supermoon?

Read about the next supermoon: June 23, 2013

When exactly is the May 2013 full moon?

Three planets close together in west this evening!

Full moon mirrors sun’s path for six months hence

When exactly is the May 2013 full moon? The May 2013 full moon falls at the same instant all over the world: May 25 at 4:25 Universal Time.

Clock time and/or date for this full moon – and every full moon – will vary by time zone. For London, the moon turns will at 5:25 a.m. BST on the morning of May 25; that means the moon will appear more full on the night of May 24-25 than on the night of May 25-26. Likewise, for the U.S. East Coast, the moon turns full on May 25 at 12:25 a.m. EDT. Meanwhile, for all places to the west of the U.S. Eastern Daylight Time zone, the moon turns full not on May 25 … but on May 24 at 11:25 p.m. CDT, 10:25 p.m. MDT and 9:25 p.m. PDT.

Technically speaking, the moon turns full at the instant that the moon lies most opposite the sun for the month. For general reference, though, we can say the moon is full all night long. Because the May 24-25 moon stays more or less opposite the sun throughout the night, watch for the full moon to rise in the east around sunrise, climb highest up in the sky around midnight and to set in the west around sunrise.

As seen from most of the world – when the moon rises on the evening of May 25 – it’ll be a waning moon.

The evening planets - Mercury, Venus and Jupiter - as they appear on May 24. They set shortly after sunset whereas the full moon stays out all night long on May 24/25. For North America, Mercury and Venus are in conjunction on the evening of May 24.

The evening planets – Mercury, Venus and Jupiter – as they appear on May 24. They set shortly after sunset whereas the full moon stays out all night long on May 24/25. For North America, Mercury and Venus are in conjunction on the evening of May 24.

Three planets close together in west this evening! Don’t spend all your time moon gazing this evening. Be sure to look toward the western sky as soon as the sun sets for three planets, Mercury, Venus and Jupiter. They are now forming a cool planetary trio – which some are, mistakenly, calling a triple conjunction. In other words, these three planets are located within a circle on the sky’s dome whose diameter is less than 5 degrees. Clouded out tonight and can’t see the planetary trio? Never fear. It’ll last through May 29. Read more about the planetary trio here.

Full moon mirrors sun’s path for six months hence Any full moon mirrors the sun’s path across the sky for six months hence. As seen from the Northern Hemisphere, tonight’s full moon will follow the low path of the late autumn sun; as viewed from southerly latitudes, the moon will follow the lofty path of the late springtime sun.

Bottom line: Full moon for May 2013 falls during the night of May 24-25. For most of us around the world, the moon will appear more full on the night of the 24th than on the 25th. This May 2013 full moon is one day away from perigee – its closest point to Earth – and so will be called a supermoon. There is a slight penumbral eclipse tonight that’s extremely difficult to detect and mainly of academic interest. We’ll all see a bright full-looking moon tonight near the bright red star Antares in the constellation Scorpius!