May brings the fringe benefits of stargazing. Rich smells of new leaves and lush green grass. Warmer nights, unburdened by winter’s frost or summer’s insects and humidity. And the slow build of birdsong that greets early-morning stargazers who steal a preview of the summer stars, or perhaps a glimpse of Jupiter as it rises before the sun in the eastern sky.
For northern-hemisphere observers, bright stars are few this month. But you can easily spot a few prominent constellations. Ursa Major (which includes the Big Dipper) is almost overhead about 9 p.m. Follow the arc of the Dipper’s handle to the bright yellow star Arcturus and then on to white Spica in the constellation Virgo. And the sickle-shape of Leo and Coma Berenices serve as signposts to the galaxies visible in larger telescope as the Earth’s sky points out of the plane of our galaxy into the rest of the universe.
For southern-hemisphere observers, the coolness of autumn is offset by an embarrassment of celestial riches. The Milky Way lies directly overhead along with the sky’s four brightest stars: Sirius, Canopus, Rigil Kent, and Arcturus. Even a casual sweep of the Milky Way’s arc reveals the star clusters and nebulae of the constellations Centaurus, Crux, Carina, and Vela.
The previous discussion posts this month by our gem member Patrick, defines almost everything special for every deep-sky junkie... and that too in his own unique perspective and in much efficient way... yet just to complete our monthly What's Up This Month post... heres a small preview again...
From both hemispheres, even a casual observer will enjoy the delights of the constellation Corvus, the Crow. Lying just north of Hydra, the Serpent, Corvus is easily distinguished by its quadrilateral shape of stars riding on the serpent’s back.
Greek legend recounts how Corvus was sent with a cup by Apollo to fetch water from a running spring. The crow complied, but stopped too long by a fig tree to gorge himself on the sweet fruit. Apollo was not amused. He confronted the crow, who falsely blamed the serpent Hydra for delaying his mission. But Apollo cast the crow and the serpent into the sky along with the cup, which we now know as the constellation Crater.
The dedicated stargazer will find dozens of galaxies in this part of the sky. But even small telescopes reveal M104, the Sombrero Galaxy, just over the Corvus-Virgo border. The beautiful spiral galaxy looks like a fuzzy oval in a small telescope. An 6-inch or larger scope reveals the central dust lane. And the Hubble Telescope reveals a breathtaking disk of stars and dust and an unusually bright galactic core.
Once you spot M104, try to find the striking asterism called “Jaws”, just half a degree west. This group of stars looks much like a celestial shark intent on dining on the great galaxy. The brightest stars of the asterism form its mouth, while the fainter stars form a long northward arc of the shark’s body. You can see both galaxy and Jaws in a low-power field of view with a telescope.
Southern observers can see omega Centauri, the sky’s brightest globular cluster, high in the sky. But May is the best month for observers at mid-to-low-northern latitudes to spot the cluster. If you’re south of 42 degrees north latitude, look for the cluster just above the southern horizon near midnight. It will look like a dim fuzzy ball made slightly orange-red by the atmospheric dust towards the horizon.
Last Quarter: May 6, 5:15 UT
New Moon: May 14, 2:05 UT
First Quarter: May 21, 0:43 UT
Full Moon: May 28, 0:07 UT
Mercury. Early last month, Mercury was as nearly as high in the sky as it ever gets. And it was uncommonly easy to find, right next to brighter Venus in the western sky at sunset. But the show’s over. The speedy planet has swung behind the sun and barely peaks above the horizon a half-hour before sunrise late in May. Diligent observers with binoculars might glimpse the planet during the last few days of the month.
Venus. The slower-moving Venus shines at a stunning magnitude -3.9 in the west-northwest sky at sunset for most of May. It’s brighter than anything else in the sky except the Sun and Moon. The planet cruises through the Hyades star cluster, the group of stars which marks the V-shaped head of the constellation Taurus. The double-star tau Tauri is just 1/2 degree west of Venus on May 4th. And on May 15th, as the crescent Moon sets, the planet passes between the stars that mark the tip of the bull’s horns.
Mars. Glowing dimly in the south at sunset, Mars is still receding from Earth and presents a tiny disk in a backyard telescope. Even the northern polar cap will be all but invisible, as summer begins in the planet’s northern hemisphere on May 12th.
Jupiter. The big planet rises in the constellation Pisces just before the sun in the east-southeast early this month. But by the end of May, it’s up by 3 a.m. The planet will put on a good show in June and July as it gets higher in the sky during peak observing hours.
Saturn. The good news? Saturn lies high in the sky right now, above the murk of the horizon and easy to find between the bright stars Regulus and Spica. The bad news? Saturn is almost as dim as it ever gets… about magnitude +1.0. The rings are just 1.7 degrees from edge-on right now and look like tiny spikes protruding from the planet. Over the next 15 years, the rings will slowly increase their inclination as seen from Earth. Even binoculars will show Saturn’s big moon Titan off to one side. You can track Titan’s motion from night to night.
Uranus is just 1 degree from Jupiter by month’s end, and will play cat and mouse with the bigger planet all summer when both are better positioned for telescopic viewing.
Neptune also rises at dawn at the border of Capricorn and Aquarius. As with Jupiter and Uranus, the planet is better seen in July and August.
The eta Aquarids meteor shower peaks around May 6 as the Earth passes through the trail of Halley’s Comet. Not a particularly fine shower, it’s best seen from low northern to mid-southern latitudes before dawn.
For casual stargazers, the fading stars of winter along with the Moon and Venus put on a lovely display at sunset on May 15.
Dazzling Venus appears just above the lovely star cluster M35 at sunset on May 21. You’ll need binoculars or a telescope at low magnification to see the pair together.
The full Moon appears south to south-west of the bright star Antares on the night of May 27.