WASHINGTON, July 31, 2015 – Tonight is the second moon, or the Blue Moon, will occur today at 10:43 Universal Time..
The idea of a blue moon is found in folklore, story and song, and it has various definitions. A Blue Moon can refer to the third of four full moons in a season. However, the common definition of the phrase, “Once In A Blue Moon” refers to the unique occurrence of a full moon twice in the same month.
To translate UTC into your local time, use the following table:
|Atlantic Daylight Time|>. subtract 3 hours from UTC|
|Atlantic Standard Time|>. subtract 4 hours from UTC|
|Eastern Daylight Time|>. subtract 4 hours from UTC|
|Eastern Standard Time|>. subtract 5 hours from UTC|
|Central Daylight Time|>. subtract 5 hours from UTC|
|Central Standard Time|>. subtract 6 hours from UTC|
|Mountain Daylight Time|>. subtract 6 hours from UTC|
|Mountain Standard Time|>. subtract 7 hours from UTC|
|Pacific Daylight Time|>. subtract 7 hours from UTC|
|Pacific Standard Time|>. subtract 8 hours from UTC|
|Alaska Daylight Time|>. subtract 8 hours from UTC|
|Alaska Standard Time|>. subtract 9 hours from UTC|
|Hawaii-Aleutian Standard Time|>. subtract 10 hours from UTC|
|Samoa Standard Time|>. subtract 11 hours from UTC|
This Blue Moon phenomena happens due to the Metonic Cycle of 19 years, when the moon completes its phases during the same month. Add 19 to 2015 and the next Blue Moon in July will happen in 2034.
However, the next Blue Moon will take place in 2018. February 2018 will not have a full moon, due to the Metonic Cycle, causing two Blue Moons that year. The first will occur -on January 31 the second will rise on March 31, 2018. And these are due to the shortened month of February.
Blue Moons were not always defined as such. The Farmer’s Almanac calls the third full moon of any season, spring, summer, fall or winter, containing four full moons a “Blue Moon” as each season usually contains 3 full moons, or a total of 12 full moons per every year.
Just as the lunar cycle causes some months to have 2 full moons, some seasons will have an extra full moon.
Tonight’s full moon offers no great fanfare. However, the waning moon on July 4th should still be large enough to create a background for Independence Day fireworks.
But it is a great month to get out your lunar calendar, grab a young person by the hand, and explore a lunar event that happens once in a blue moon.
Throughout June skywatchers have been watching the dance between Jupiter and Venus, which continues tonight when the “dazzling planets stand side by side in the west, still with just a full moon’s width between them,” Astronomy.com says. Watching over them will be the full moon. “Only the full moon itself—climbing higher in the southeastern sky this evening—appears brighter.”
That moon becomes full at precisely 10:20 p.m. EDT.
As for Venus and Jupiter, we will not see the likes of this sky event for more than a year, says Earthsky.org.
“Venus and Jupiter both appear bright in Earth’s sky because the cloud cover on these worlds effectively reflects sunlight,” says Earthsky.org. “Although Jupiter is so much farther off than Venus, Jupiter’s sheer size guarantees the king planet’s brilliance. This is their closest pairing in the evening sky until August 27, 2016.”
This Science.Nasa.Gov video is dated August 2014, however it offers a great explanation of the planets and how Venus and Jupiter converge. Tonight, look for the moon to between the two bright planets. Also still visible in the Western sky is Saturn.
For novice skywatchers, a great app is PlanetFinder. For less than a few dollars, your smartphone becomes a planet, star and constellation identifier.