Sky at a Glance, May 9 – 17

Friday, May 9

The waxing gibbous Moon in the evening sky forms a curving line with Mars to its left, and Spica to the lower left of Mars.

Full Moon and Saturn

North Americans see the Moon hop across Saturn from one night to the next. Australians will see the Moon crossing right over Saturn in their nighttime, occulting it.

Saturday, May 10

Bright Mars shines left of the Moon. Although they look rather close together, Mars is 260 times farther away — and twice as big in diameter.

Sunday, May 11

Now the Moon is positioned between Mars and Spica (for the Americas in the evening).

Jupiter shines within the western Arch of Spring as twilight fades. The top of the Arch is formed by Pollux and Castor, roughly horizontal. To their lower left is Procyon, the left end of the Arch. The right end is formed by Menkalinen and then Capella. Jupiter is gradually moving toward the Arch's upper left side.

Monday, May 12

Three zero-magnitude stars shine after dusk in May: Arcturus high in the southeast, Vega much lower in the northeast, and Capella in the northwest. They appear so bright because each is at least 60 times as luminous as the Sun, and they're all relatively nearby: 37, 25, and 42 light-years from us, respectively.

Dawn view

By the beginning of dawn, the bright Moon and its surroundings are moving low in the southwest.

Tuesday, May 13

The bright Moon, practically full, shines near Saturn. The Moon creeps to come within 1° to 3° of Saturn before dawn Wednesday morning for the Americas. For New Zealand and most of Australia, the Moon occults (covers and uncovers) Saturn during nighttime; map and timetables.

Wednesday, May 14

Full Moon (exact at 3:16 p.m. Eastern Daylight Time.) Look for Saturn to its upper right. Once the Moon is well up after dark, look for Antares and the other stars of upper Scorpius below it. By dawn they're lying down in the southwest.

Thursday, May 15

Jupiter's moon Io crosses the face of the planet from 9:41 to 11:57 p.m. Eastern Daylight Time. Io's tiny but more visible shadow follows it across from 10:42 p.m. to 12:59 a.m. EDT.

Friday, May 16

Look for Mercury as twilight darkens. It's low in the west-northwest, far to the lower right of Jupiter. Mercury is coming into its highest apparition of 2014 for skywatchers at mid-northern latitudes.

Saturday, May 17

Arcturus shines high in the southeast these evenings. Vega shines much lower in the northeast. Look a third of the way from Arcturus to Vega for dim little Corona Borealis, the Northern Crown, with its one modestly bright star, Alphecca or Gemma. Two thirds of the way from Arcturus to Vega glimmers the dim Keystone of Hercules.


Want to become a better astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.

This is an outdoor nature hobby. For an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential guide to astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

Pocket Sky Atlas

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6 — about as faint as show in a typical good finderscope. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae.

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The standards are the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and once you know your way around, the even larger Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts with a telescope.

You'll also want a good deep-sky guidebook, such as Sue French's Deep-Sky Wonders collection (which includes its own charts), Sky Atlas 2000.0 Companion by Strong and Sinnott, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

Can a computerized telescope replace charts? Not for beginners, I don't think, and not on mounts and tripods that are less than top-quality mechanically (able to point with better than 0.2° repeatability, which means fairly heavy and expensive). As Terence Dickinson and Alan Dyer say in their invaluable Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."


This Week's Planet Roundup

Mars-by-Rick-Schrantz_5-7-2014

Mars on May 7th, imaged by Rick Schrantz from his patio in Nicholasville, Kentucky. He used a homemade 10-inch f/7.5 reflector at f/43 with a DMK21AU618.AS planetary video camera. South is up. The light patches near center are thin clouds over Elysium. The dark band at upper left is Mare Cimmerium.

Jupiter by Christopher Go, May 12, 2014

Jupiter on May 12th as imaged by Christopher Go in the Philippines. South is up. Notice how chopped up this stretch of the North Equatorial Belt is on its border with the Equatorial Zone. (The central-meridian longitude is 160°.) To get an idea of the visual telescopic appearance, brighten the image, reduce the contrast, stand back and squint your eyes. The raggedness of the NEB's southern edge is still quite visible.

Saturn-by-Damien-Peach_April-14-2014

You never see images of Saturn taken from Earth finer than this. Damien Peach in the U.K. used a 12-inch Schmidt-Cassegrain scope, and many years of experience, to obtain this view on April 14th. South is up. He writes, "Many fine details can be seen in this true RGB image. Note the small white spot in the mid-northern latitudes [very subtle!]. Otherwise things look very quiet. "

Mercury (about magnitude –1.0) is emerging into better view in evening twilight every day. Look for it low in the west-northwest, very far to the lower right of bright Jupiter, about 40 to 60 minutes after sundown.

Venus (magnitude –4.1) is the bright "Morning Star" low due east during dawn. How late into the brightening daylight can you follow it?

Mars (magnitude –1.0, in Virgo) shines highest in the south shortly after dark. Just left of it is 3rd-magnitude Gamma Virginis (Porrima). Far lower left of Mars sparkles Spica.

In a telescope Mars shrinks this week from 13.9 to 13.2 arcseconds wide as it becomes more gibbous. See the Mars map and observing guide in the March Sky & Telescope, page 50. Use our Mars Profiler to find which side of the planet will be facing Earth when you plan to look.

Jupiter (magnitude –2.0, in Gemini) shines high in the west in twilight, under Pollux and Castor. It sinks during the evening and sets around midnight. In a telescope Jupiter has shrunk to 34″ across its equator.

Saturn (magnitude +0.1, in Libra) is at opposition May 10th. It rises around sunset, shines in the southeast during evening, and stands highest in the south around midnight or 1 a.m. Look for Antares and the head of Scorpius to its lower left.

Uranus and Neptune are still fairly low before or during dawn.


"We may be little guys, but we don’t think small. It’s the courage of questions, of grasping our true circumstances, and not pretending we are at the center of it all, that is adulthood."
— Ann Druyan, 2014. The remade Cosmos series continues on Sunday nights on Fox and Mondays on National Geographic. Watch online anytime.


All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America.

Eastern Daylight Time (EDT) is Universal Time (UT, UTC, or GMT) minus 4 hours.