Moon Phases
Full Moon
Sunday, May 3, 11:42 p.m. EDT
The Full Moon of May is known as the “Milk Moon,” “Flower Moon,” or “Corn Planting Moon.” It rises around sunset and sets around sunrise; this is the only night in the month when the Moon is in the sky all night long. The rest of the month, the Moon spends at least some time in the daytime sky.
Last Quarter Moon
Monday, May 11, 6:36 a.m. EDT
The Last Quarter Moon rises around 2 a.m. and sets around 1 p.m. It is most easily seen just after sunrise in the southern sky.
New Moon
Sunday, May 18, 12:13 a.m. EDT
The Moon is not visible on the date of New Moon because it is too close to the Sun, but can be seen low in the East as a narrow crescent a morning or two before, just before sunrise. It is visible low in the West an evening or two after New Moon.
First Quarter Moon
Monday, May 25, 1:19 p.m. EDT
The First Quarter Moon rises around 1 p.m. and sets around 2:15 a.m. It dominates the evening sky.
Observing Highlights
Mercury at greatest elongation
Thursday, May 7, evening twilight
This is the best evening apparition of Mercury this year for observers in the northern hemisphere. Use Venus to help you locate it. Mercury is most easily located by sweeping with binoculars, but once you’ve located it, you should be able to see it with your unaided eyes
Uranus and the Moon
Friday, May 15, dawn
The Moon will pass just south of the Uranus just before sunrise.
Double shadow transit on Jupiter
Wednesday, May 20, 8:06–8:35 p.m. EDT
The shadows of Io and Ganymede will be on opposite limbs of Jupiter, while the moons Io and Callisto will be central on the disk.
Saturn at opposition
Friday, May 22, 10 p.m. EDT
Saturn will be in opposition to the Sun.
Note how most of Saturn’s moons are in the same plane as the rings, except for Iapetus, whose orbit is tilted 8.3 degrees. At opposition, Iapetus is close to maximum elongation towards the west, while Tycho is close to maximum elongation towards the east.
Double shadow transit on Jupiter
Wednesday, May 27, 10:01 p.m.–12:18 a.m. EDT
The shadow of Io chases the shadow of Ganymede across the face of Jupiter, catching up with it and passing it at 11:48 p.m. EDT. The Great Red Spot will also cross Jupiter’s disk during this period.
Planets
Mercury is well placed for northern hemisphere observers in the evening twilight sky for the first three weeks of May.
Venus shines high in the western sky after sunset.
Mars moves from Aries to Taurus on May 3, too close to the Sun to be visible.
Jupiter is well placed in the evening sky all month.
Saturn is just north of Scorpius’ “claws.” At opposition on May 22, it is visible all night.
Uranus rises just before the Sun in Pisces.
Neptune is in the eastern morning sky in the constellation Aquarius.
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