The full Pink Moon peaks this weekend on Sunday, April 29, at 8:58 p.m. EDT (0058 GMT on April 30), offering a fine view for after-dinner skywatchers in the eastern U.S.
New Yorkers will see the nearly full moon rise at 7:31 p.m. EDT. The moon and sun will share the sky for a short time, because the sun sets over New York about 20 minutes after moonrise. Farther south, the two bodies will be visible in the sky together for an even shorter time; Miami observers will see moonrise at 7:41 p.m. EDT and sunset at 7:50 p.m. EDT, according to timeanddate.com.
For casual observers, the moon looks pretty full a day before and after the actual full phase, which is defined as when the moon is exactly on the opposite side of the Earth from the sun. The timing of the full moon’s appearance depends on where the moon is in its orbit around the Earth; this is why the actual time of the full moon can be in daylight for certain locations. [The Moon: 10 Surprising Facts]
In addition, the moon’s orbit isn’t perfectly circular; it’s a bit elliptical, so the interval between full moons isn’t perfectly regular.
The phases of the moon are determined by how much of the moon’s visible face is illuminated by the sun.
The phases of the moon occur because we see our satellite from different perspectives as it revolves around the Earth. When the moon is 90 degrees to the left or right of the imaginary line connecting the Earth and sun, the satellite is half-illuminated. This is called a quarter moon, because the moon is a quarter of the way around its orbit.
A careful observer might see the moon move east about a half a degree, or one moon diameter, per hour on any given night. This is because the satellite is relatively close to Earth as astronomical objects go. Over the course of a 12-hour night, that’s 6 degrees, which can take the moon right out of one constellation and into another. [How to Measure Distances in the Night Sky]
About a week before the full moon, the Lyrid meteor shower will occur, peaking overnight on April 22-23. The moon will be at first quarter at that time and will set by midnight, leaving the sky darker and better for meteor watching. A few stray meteors are visible on any night, and even a week after a meteor shower peaks, some stragglers can still be seen. However, on a night with a full moon it is much harder to see them, because the moon’s light washes out fainter objects.
On the day of the full moon, several naked-eye planets will also be visible, though not at the same time. Venus will be about 21.7 degrees above the horizon for New York City, according to heavens-above.com calculations. The planet rises at 7:19 a.m. EDT, when the sun is already in the sky (sunrise will be at 5:57 a.m. EDT). Venus will set below the horizon at 10:03 p.m. EDT, roughly 2 hours after sunset. This planet is the third-brightest object in the sky after the sun and the moon, so it should be easy to spot just south of due west.
Jupiter will rise at 8:31 p.m. EDT, followed by Saturn at 12:24 a.m. EDT (on April 30) and Mars at 1:28 a.m. EDT. Both planets are going to be bright enough to compete with even a full moon (or city lights). In the predawn hours (between 3 a.m. and 4 a.m. local time), Saturn and Mars will be relatively high in the sky. The two planets will be between 18 and 25 degrees above the horizon in New York City. Farther south, they’ll appear even higher in the sky.
As for the moon, it will be in the constellation Libra, along with Jupiter. Libra is a faint constellation and is not very visible from most urban locations, but the moon and Jupiter will be relatively close together in the sky, marking the spot. (The full moon tends to overwhelm many stars in Libra in any case).
To the east of both the moon and Jupiter, one can see the star Spica, which is the brightest star in Virgo. A similar configuration occurred during April’s full moon last year, but this time, the moon and Jupiter won’t be as close together as they were then.
April’s full moon is known as the Pink Moon, according to the Old Farmer’s Almanac. The name comes from pink flowers that bloom in the early spring, known as ground phlox. This month’s full moon has also been called the full Sprouting Grass Moon, the Egg Moon and the Fish Moon.
For most of human history, the moon was largely a mystery. It spawned awe and fear and to this day is the source of myth and legend. But today we know a lot about our favorite natural satellite.
This year, Easter fell on April 1, because of the Blue Moon on March 31 — the second full moon in March. Usually, April’s full moon marks the time of Easter and Passover. Easter is always observed on the first Sunday after the first full moon in spring, known as the Paschal Moon. Theravada Buddhist traditions use the full moon of April to mark the new year; this version of the new year is widely celebrated in Thailand, Myanmar and Sri Lanka.
The Māori people of New Zealand had a different tradition for their April moons, because in the Southern Hemisphere, April is in the fall. They 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.