The May Night Sky
See what's up in the night sky for May 2019, including stargazing events and the moon's phases, in this Space.com gallery courtesy of Starry Night Software.
In the eastern pre-dawn sky of Thursday, May 2, the old crescent moon will land 4 degrees to the lower right (south) of bright Venus. At the same time, much dimmer Mercury will be sitting just above the horizon, and 10 degrees to the left of the moon. While the moon and Venus will remain visible until sunrise, Mercury will vanish into the dawn twilight after about 4:30 a.m. local time.
Saturday, May 4 at 22:45 GMT — New Moon
At its new phase, the moon is traveling between the Earth and the Sun. Since sunlight can only reach the side of the moon pointed away from us, and the moon is in the same region of the sky as the sun, the moon is hidden from view for Earth-bound observers. A day or two after new moon, look for the slender sliver of the young crescent moon sitting just above the western horizon after sunset.
Saturday, May 5 pre-dawn — Eta-Aquariid Meteor Shower Peak
The annual Eta-Aquariid Meteor Shower, produced by material from Halley's Comet, runs from April 19 to May 26 and peaks before dawn on Sunday, May 5. True Aquariids will appear to travel away from a radiant point in Aquarius, near the southeastern horizon. The southerly radiant makes this shower better for observers at low latitudes. Watch for up to a few dozen meteors per hour, including some fireballs, near the peak. The very young evening moon will leave the sky nice and dark for this shower.
Monday, May 6 evening — Moon near Aldebaran
In early evening on Monday, May 6, in the west-northwestern sky, the moon will be positioned above the stars forming Taurus' triangular face, and that constellation's brightest star, Aldebaran. Use binoculars (orange circle) to capture the scene. Observers in Europe, Africa, and Asian will see the moon pass through Taurus' face after dusk.
Tuesday, May 7 early evening — Crescent Moon meets Mars in Taurus
In the western sky on the evening of Tuesday, May 7, the waxing crescent moon will land 3.5 degrees to the lower left (south) of reddish Mars. A medium-bright star named Zeta Tauri (ζ Tauri) will be positioned close to the higher tip of the moon's crescent. That star marks the eastern horn of Taurus, the Bull.
Friday, May 10 evening — Moon Buzzes the Beehive
In the western sky after dusk on Friday, May 10, the nearly first quarter moon will pass almost directly through the large open star cluster in Cancer known as the Beehive, Praesepe, and Messier 44. The moon will be centered on the cluster at approximately 10 p.m. EDT. Binoculars or a telescope at low magnification (orange circle) will show both the moon and the cluster at the same time. To better see the clusters' stars, try to position the moon just outside of your optics' field of view.
Sunday, May 12 at 1:12 GMT — First Quarter Moon
At first quarter, the relative positions of the Earth, sun, and moon cause us to see the moon half illuminated — on the eastern (right-hand) side. First quarter moons rise around noon and set around midnight, so they are visible starting in the afternoon hours. The term quarter moon refers not to its appearance, but the fact that our natural satellite has now completed the first quarter of its orbit around Earth since the last new moon.
Saturday, May 18 pre-dawn — Venus Passes Uranus
On Saturday, May 18, Venus' rapid orbital motion toward the sun (red curve) will carry it past distant Uranus. The two planets will sit low over the east-northeastern horizon before dawn, making dim Uranus difficult to see.
Saturday, May 18 at 21:11 GMT — Full Milk Moon
The May full moon, known as the Full Milk Moon, Full Flower Moon, or Full Corn Planting Moon, always shines in or near the stars of Libra. Full moons always rise in the east as the sun sets, and set in the west at sunrise. Since no shadows are cast by the vertically impinging sunlight on a full moon, all of the brightness differences are generated by the reflectivity, or albedo, of the surface geology. This year we celebrate the 50th anniversary of the first footsteps by humans on the moon.
Sunday, May 19 evening — Mars Attacks Messier 35
In the north-northwestern sky on the evening of Sunday, May 19, the reddish planet Mars will be positioned only 0.25 degrees (or half the full moon's diameter) above (northeast) of the prominent open star cluster known as Messier 35 and NGC 2168. Mars and the star cluster's many stars will all fit together into the field of view of a backyard telescope at medium magnification (red circle). (Your optics might flip and/or invert the view.) Binoculars will also show this cluster under moderately dark skies. Look for another, dimmer open cluster designated NGC 2158 sitting below M35.
Sunday, May 19 overnight — Gibbous Moon moves with Jupiter
When the waning gibbous moon rises from the southeastern horizon after 10 p.m. local time on Sunday, May 19, it will be positioned only 7 degrees to the upper right (west) of bright Jupiter. As the pair crosses the night sky together, the moon's orbital motion (red line) will carry it noticeably closer to Jupiter. The pairing will remain visible until just before sunrise, at which time, they will be over the south-western horizon.