This Week's Sky at a Glance, August 8 – 16;

Friday, August 8

Already you may see an occasional Perseid meteor if you keep an eye on the night sky. The shower's peak night is predicted for next Tuesday (August 12–13), but moonlight will compromise the view all week.

Look northeast as the stars come out for W-shaped Cassiopeia. It's still not quite as high as the Big Dipper is in the northwest, but the two are on their way to their dusk balance point week by week. Get a preview of this by checking on them around 11 p.m. (depending on your location).

Saturday, August 9

If you're in the Earth's mid-northern latitudes, bright Vega passes close by your zenith around 10 or 11 p.m. (depending on where you live east-west in your time zone). Wherever you are, Deneb always passes the zenith two hours after Vega.

Sunday, August 10

Largest full Moon of the year, but not by much. Can you really detect any difference? The Moon is only 8% larger than average. See our article, The Not Very Supermoon.

Monday, August 11

Mars is pulling a little closer to Saturn every day. Spot them in the southwest at dusk; Mars is the one on the lower right. Tonight they're still 8° apart. Look farther to the lower right of Mars for twinkly Spica.

Tuesday, August 12

Peak Perseid meteor night late tonight. But the Moon, just two days after full, compromises the view. See our article, Perseids vs. Moonlight: Which Will Prevail?.

Wednesday, August 13

The waning gibbous Moon rises in the east just about at the end of twilight. Look above the Moon (or above where it's just about to rise) for the Great Square of Pegasus, larger than your fist at arm's length and standing on one corner.

Thursday, August 14

Vega is almost overhead after dark. The brightest star in the southeast is Altair, nearly as bright. Altair is flagged by little Tarazed (3rd magnitude) a finger-width above it: an orange giant far in Altair's background.

Friday, August 15

For the next several mornings, look low in the east-northeast about 45 to 30 minutes before sunrise for Venus and Jupiter very close together. On Saturday morning, these two brightest planets are still 1.8° apart. They'll be closest on Monday morning the 18th: just 0.2° apart at the time of dawn for Europe, 0.3° by the time dawn reaches the Americas.

Saturday, August 16

The two brightest stars of summer are Vega, overhead soon after dark, and Arcturus, shining in the west. Vega is a white-hot type-A star 25 light-years away. Arcturus is an orange-yellow-hot type-K giant 37 light-years distant. Their color difference is fairly clear to the unaided eye. Both are dozens of times more luminous than the Sun.

 

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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).

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 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."

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This Week's Planet Roundup

Mercury is out of sight in the glare of the Sun.

Venus (magnitude –3.8) and Jupiter (a sixth as bright at magnitude –1.8) shine close together low in the east-northeast during dawn. They're in conjunction on the morning of the 18th, just 0.2° or 0.3° apart.

Mars and Saturn, identically bright at magnitude +0.5, glow in the southwest at dusk. Mars is the lower one. Look to their left for the head of Scorpius, highlighted by Delta Scorpii, and then Mars-colored Antares.

The two planets are closing in on each other. They'll pass 3½° apart on August 23–26.

Uranus (magnitude 5.8 in Pisces) and Neptune (magnitude 7.8 in Aquarius) are well placed in the southern sky in the early-morning hours. Finder charts for Uranus and Neptune.

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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.

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