Sky at a Glance, May 2 – 10

Twilight sky view with Moon and Jupiter

Watch the waxing crescent Moon pass between Jupiter above and Betelgeuse below.

Friday, May 2

How soon after sunset can you see the first stars and planets coming out? The brightest this spring is Jupiter. Look for it high in the west, almost two fist-widths at arm's length above or upper left of the Moon this evening. Next brightest is Sirius, sinking in the southwest.

Saturday, May 3

The waxing crescent Moon shines below Jupiter in the west at dusk. Above Jupiter are Pollux and Castor. Left of it is Procyon.

Sunday, May 4

Now the Moon shines to Jupiter's left at nightfall. The Moon moves eastward an average of 13° per day with respect to the background stars, a little more than the width of your fist at arm's length.

Monday, May 5

The Moon forms a rough rectangle in the evening with Procyon below it, Jupiter to Procyon's right, and Pollux above Jupiter.

Before the Moon waxes further and lights the night sky, check in on the faint "new Comet PanSTARRS," Comet C/2012 K1, under the handle of the Big Dipper. Use the finder chart in the May Sky & Telescope, page 50. It's currently being reported at about magnitude 9.0, a little fainter than originally predicted, with no tail visible in a 6-inch scope at 36×.

The Eta Aquariid meteor shower peaks before dawn's first light Tuesday morning. The shower is often the year's richest for Southern Hemisphere observers. From mid-northern latitudes the shower's radiant point doesn't rise very high before dawn, so fewer are seen, but those that do appear are long "earthgrazers" skimming the upper atmosphere, more dramatic than short meteors coming straighter down.

Tuesday, May 6

First-quarter Moon (exactly so at 11:15 p.m. Eastern Daylight Time). The Moon shines in Cancer above the dim head of Hydra. Well to the Moon's upper left is Regulus, forming the bottom of the Sickle of Leo.

Wednesday, May 7

Just above the Moon at nightfall are Regulus and the Sickle of Leo.

Thursday, May 8

Sometime late this evening (roughly 10 p.m. depending on where you live), bright Capella declining in the northwest will be exactly as high as bright Vega climbing in the northeast. How accurately can you time their altitude balance? Each day it will come four minutes earlier.

Friday, May 9

The waxing gibbous Moon forms a curving line tonight with Mars to its left and Spica to Mars's lower left.

Saturday, May 10

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


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 — which may sound like a lot, but it's still less than one per square degree on the sky. 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 on April 24, 2014

On April 24th, as seen at nighttime in the Philippines, Mars was displaying a thin orographic (mountain-generated) cloud over Olympus Mons near center and bright clouds in the Chryse region near the evening limb (left; celestial west). South is up; the North Polar Cap is at bottom. The large diagonal dark region at upper right is Mare Cimmerium.
Christopher Go.

Mercury (about magnitude –1.2) is emerging into view very low in the sunset. Look for it above the west-northwest horizon about 30 minutes after sundown. Binoculars help. Mercury will become a little higher and easier to spot each day.

Venus (magnitude –4.2) is the bright "Morning Star" low in the east during dawn. How late into the growing daylight can you follow it?

Mars (magnitude –1.0, in Virgo) shines in the southeast to south during evening. Just left of it is 3rd-magnitude Porrima. Far lower left of Mars sparkles Spica.

In a telescope Mars is still 14 arcseconds wide, though it will soon start shrinking faster. 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 you when you plan to look.

Jupiter with Red Spot and Io shadow transit

Jupiter on April 28th, imaged by Christopher Go at 10:40 UT. South here is up. The black shadow is Io's. Io itself is nearing the planet's left (celestial west) limb, on the edge of the Equatorial Zone and South Equatorial Belt. Thick white turbulence roils behind the Great Red Spot, and the Red Spot Hollow shows a gray outline, especially on its following side.

Jupiter (magnitude –2.0, in Gemini) shines high in the southwest in twilight. It sinks westward through the evening and sets around midnight or 1 a.m. In a telescope it has shrunk to 35″ across its equator.

Saturn (magnitude +0.1, in Libra) comes to opposition May 10th. It rises around sunset, shines in the southeast during evening, and stands highest in the south around 1 a.m. By then it's far left of Mars, and half as far to the upper right of Antares.

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 through June 13th. Episode guide. 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.