Sky at a Glance | August 9th, 2013

Supernova in M74. The supernova in the spiral galaxy M74 was still magnitude 12.5 as of August 8th, and turning from white to pale yellow. It's in Pisces, well up in the east by 2 a.m. See our article Supernova Erupts in M74, and see its up-to-date light curve.


Dusk view
Back in the evening sky, the waxing crescent Moon passes Venus and Saturn.

Friday, August 9

  • Early in twilight, about a half hour after sunset, look very low in the west below Venus for the thin crescent Moon, as shown at right. Binoculars will help.

  • The Perseid meteor shower is ramping up! Activity is already well under way, and the shower should peak late Sunday and Monday nights. Read all about it: Get Ready for the 2013 Perseids.

    Saturday, August 10

  • The waxing crescent Moon shines well to the left of Venus low in twilight, as shown above.

    Sunday, August 11

  • The annual Perseid meteor shower should be at its most active late tonight and tomorrow night. (The expected peak time, 2 p.m. EDT August 12th, is ideal for the Far East; for North America it splits the difference between the early morning hours of the 12th and 13th.) See our article Get Ready for the 2013 Perseids.

    Monday, August 12

  • During and after dusk, spot Saturn above the waxing crescent Moon in the southwest. Look lower right of the Moon for Spica. Much higher to their upper right shines Arcturus.

    Tuesday, August 13

  • The first-quarter Moon shines in the southwest at nightfall, with Saturn to its right and Antares farther to its left. Quite close to the Moon is Alpha Librae, a wide double star for binoculars. The Moon occults (covers) Alpha Librae for much of South America.

    Moon and Scorpius
    The Moon waxes across upper Scorpius...
    Moon over Sagittarius
    ...and then shines above the Teapot of Sagittarius.

    Wednesday, August 14

  • Look for orange Antares lower left of the Moon after dusk, with the other stars of upper Scorpius around it. Near the zenith shines the Summer Star, Vega.

    Thursday, August 15

  • Antares is lower right of the Moon this evening.

    Friday, August 16

  • By about 10 p.m. (depending on where you live), W-shaped Cassiopeia is now as high in the northeast as the Big Dipper is in the northwest. Cassiopeia will grow more ascendant over the Dipper in the evening for the next several months as the seasons turn.

  • Look below the Moon tonight and tomorrow night for the Sagittarius Teapot, as shown below.

    Saturday, August 17

  • The waxing gibbous Moon shines high in the south after nightfall. Look high to its upper left for bright Altair. Just above Altair is 3rd-magnitude Tarazed, an orange giant star (can you see its tint?) 20 times farther away.


    Want to become a better amateur 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 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 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


    Mercury, Mars, and Jupiter shine in the east-northeast before and/or during dawn. Jupiter is the highest and brightest (magnitude –1.9). Look for faint Mars (magnitude +1.6) increasingly far to Jupiter's lower left. Both are in Gemini, with Pollux and Castor to Mars's left.

    Look far down to Mars's lower left, as dawn brightens, for Mercury (magnitude —1). It's sinking lower every day. Don't confuse Mercury with Procyon, far down to Mars's lower right.

    Venus (magnitude –3.9) shines brightly very low in the west in evening twilight. In a telescope Venus is still small (13 arcseconds) and gibbous (80% sunlit).

    Saturn (magnitude +0.7, between Virgo and Libra) glows in the southwest as twilight fades, with Spica 12° to its lower right. High to their upper right is brighter Arcturus.

    Uranus (magnitude 5.8, in Pisces) and Neptune (magnitude 7.8, in Aquarius) are both in view in the southeast by midnight. Finder charts for Uranus and Neptune.


    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) equals Universal Time (also known as UT, UTC, or GMT) minus 4 hours.


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