The full moon of April, called the Pink Moon, will occur on Tuesday (April 7) at 10:35 p.m. EDT (0235 GMT on April 8), about 8 hours after reaching perigee, the nearest point from Earth in its orbit. This will create a "supermoon," a full moon that appears slightly larger than average.
The smaller distance between Earth and the full moon makes the supermoon appear about 7% larger than the average full moon and 14% larger than a full moon at apogee, or its farthest distance from Earth — also known as a "minimoon." A supermoon also appears up to 30% brighter than a full moon at apogee.
Skywatchers in the U.S. can see the "Super Pink Moon" rise into the evening sky as the sun sets on Tuesday. In New York City, for example, moonrise is at 7:05 p.m. local time on the evening of April 7, and moonset is the next morning at 7:05 a.m., according to timeanddate.com. The sun sets the evening of April 7 at 7:26 p.m.
Being in the constellation Virgo, the moon will be to the northeast of Spica, the brightest star in Virgo and the 16th-brightest star in the night sky. The moon will be in the constellation Virgo, and it have an angular diameter of 0.56 degrees, just slightly larger than its average of 0.52 degrees across, so the difference in size won't be noticeable to most people.
The moon reaches perigee, or its closest point to Earth, at 2:08 p.m. EDT (1808 GMT), according to NASA's SkyCal. The moon reaches perigee about once every 28 days, because its orbit isn't a perfect circle. However, we don't have a supermoon every month because the moon's perigee typically doesn't coincide with a full moon. During its perigee on April 7, the moon will be 221,905 miles (357,122 kilometers) from the Earth, versus an average distance of 240,000 miles (384,400 km).
When the full moon coincides with perigee, it is sometimes called a "supermoon" — but "supermoon" isn't an official term used by astronomers. Whether a full moon counts as "super" depends on how close to the official full moon the user of the word thinks perigee should be. Some astronomers define a "supermoon" as the one full moon in a calendar year that most closely coincides with the moon's perigee, while others use the term more loosely, calling any full moon that occurs within a day or so of perigee "super."
The full moon occurs when the moon is exactly on the opposite side of the Earth from the sun. Most of the time the moon is illuminated by the sun's light, but occasionally the moon's orbit carries it within the shadow of the Earth, resulting in a solar eclipse. The April full moon will "miss" the Earth's shadow, because the moon's orbit is inclined 5 degrees with respect to the plane of the Earth's orbit, and therefore the Earth won't be directly between the sun and the moon this time.
Through binoculars or a small telescope the full moon appears so bright it can be hard to see details, because there are no shadows to give any contrast. From a lunar observer's perspective the sun would be directly overhead — it would be noontime. Moon filters are available that can make some features stand out, but waiting a few days after the full moon or observing a few days before, shadows bring out more detail.
Planets on parade
On April 9, two days after the full moon, the planet Jupiter, which is prominent in the predawn sky, will be in conjunction with Pluto, meaning the two objects share the same celestial longitude and will make a close approach in the night sky.
The dwarf planet Pluto is beyond the reach of most amateur telescopes, as its visual magnitude is 15. (Magnitude is a scale astronomers use to denote an object's brightness, with smaller numbers indicating brighter objects. The dimmest objects visible with the naked eye are typically of magnitude 6.5.)
A telescope with a 10-inch (25 centimeters) aperture or more is necessary to see Pluto, and the object itself doesn't look any different from stars through the eyepiece. But Jupiter is naked-eye visible and an easy "catch" for a telescope. The conjunction occurs at 3:02 a.m. EDT (0702 GMT), according to In-The-Sky.org. Both Jupiter and Pluto will be in the constellation Sagittarius.
Other planets visible on the night of April 7-8 are Mars and Saturn, which will be close to Jupiter in the early morning hours before sunrise. As the full moon is in the west on the morning of April 8 the three planets will be in a rough line in the east-southeastern sky. By 4:30 a.m. local time in mid-northern latitudes on April 8, Mars will be about 9 degrees above the horizon, with Saturn slightly higher to the right and Jupiter to the right of that (from the point of view of an observer). For reference, your clenched first held at arm's length measures about 10 degrees wide.
The Pink Moon isn't really pink.
Despite its moniker, the Pink Moon isn't actually pink. The name "Pink Moon" comes from the bloom of ground phlox, a pink flower common in North America, according to The Old Farmer's Almanac. It has also been called the Sprouting Grass Moon, the Egg Moon and the Fish Moon.
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According to the Ontario Native Literacy Coalition, the Ojibwe peoples indigenous to North America called it the Sucker Moon after the common fish species known as suckerfish. This fish, also known as the remora, is one of the animals that the Ojibwe saw as a messenger between the spirit world and ours. In the same region, the Cree called April's full moon the Goose Moon, as April was the month when geese returned to the north after migrating south for the winter.
The Tlingit of the Pacific Northwest call the April full moon "X'eigaa Kayaaní Dís," meaning "Budding moon of plants and shrubs," according to the Tlingit Moon and Tide Teaching Resource published by the University of Alaska at Fairbanks.
In New Zealand, the Māori people had much different traditions for their April full moons, because in the Southern Hemisphere, April arrives in autumn. The Māori called the April moon "Paenga-whāwhā," describing the month as a time when "all straw is now stacked at the borders of the plantations," according to The Encyclopedia of New Zealand.
For the Jewish people, April 9 marks the beginning of the holiday of Passover (the 15th day of the lunar month of Nisan), which celebrates the escape from Egypt and has been popularized by films such as "The Ten Commandments" and Disney's "The Prince of Egypt."
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