Sky at a Glance | June 28th, 2013

The July waning crescent Moon passes landmarks of Taurus. The visibility of faint objects in twilight is exaggerated here; binoculars help. The blue 10° scale is about the width of your fist at arm's length.

Friday, June 28

  • The Big Dipper, still high in the northwest, is moving a little lower now and starting to dip around toward the right. Follow the curve of its handle a little more than a Dipper-length left, and you land on bright Arcturus high in the southwest.

    Saturday, June 29

  • This is the time of year when, after dark, the dim Little Dipper floats straight upward from Polaris (the end of its handle) — like a helium balloon on a string escaped from some summer evening party.

    Sunday, June 30

  • Vega is the brightest star high in the east. Right next to Vega lies one of the best-known multiple stars in the sky: 4th-magnitude Epsilon (ε) Lyrae, the Double-Double. It forms one corner of a roughly equilateral triangle with Vega and Zeta (ζ) Lyrae. The triangle is less than 2° on a side. A 4-inch telescope at 100× or more should resolve each of Epsilon's two wide components into a tight pair.

    Zeta Lyrae is also a double star for binoculars; much tougher, but easily split with a telescope.

    Monday, July 1

  • If you have a dark enough sky, the Milky Way now forms a magnificent arch high across the whole eastern sky after nightfall is complete. It runs all the way from below Cassiopeia low in the north-northeast, up and across Cygnus and the Summer Triangle in the east, and down past the spout of the Sagittarius Teapot in the south-southeast.

    Tuesday, July 2

  • The Big Dipper, high in the northwest after dark, is turning around to "scoop up water" through the nights of summer and early fall.

    For this conjunction don't just bring binoculars, bring a telescope. Good luck.

    Wednesday, July 3

  • A twilight challenge: As twilight fades, spot Venus low in the west-northwest. As darkness deepens, can you make out stars of the Beehive Cluster within about ½° below it? Good luck — the brightest of them are 6th magnitude, about 10,000 times fainter than Venus!

  • A much easier challenge: Look ½° above Saturn soon after dark for the 4.2-magnitude star Kappa Virginis.

    Thursday, July 4

  • Watching the fireworks tonight? As you're waiting for them to begin, point out to people some sky sights. The two brightest stars of summer, Vega and Arcturus, are high overhead toward the east and southwest, respectively. Far below Arcturus are the planet Saturn and, to its lower right, Spica. Nearly that high in the southeast is the orange-red supergiant Antares, amid fainter stars of upper Scorpius.

    As the waning Moon thins to a hairline crescent low in bright dawn, use it to guide your way to other low sights. Bring binoculars.

    Friday, July 5

  • During dawn this morning and Saturday morning, look low in the east-northeast for the waning Moon. It guides your way to Mars, Jupiter, Aldebaran, and Beta Tauri, as shown at right. Binoculars will help.

  • Earth is at aphelion, its farthest from the Sun for the year (just 1 part in 30 farther than at perihelion in January).

    Saturday, July 6

  • Two hours after sunset, after darkness is truly complete, the east-northeast horizon bisects the Great Square of Pegasus across two of its opposite corners. By midnight the whole Great Square is up in good view, balancing on its bottom corner.

    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.

    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 that's less than one star in an entire telescopic field of view, on average. By comparison, Sky Atlas 2000.0 plots 81,312 stars to magnitude 8.5, typically one or two stars per telescopic field. Both atlases include many hundreds of deep-sky targets — galaxies, star clusters, and nebulae — to hunt among the stars.
    Sky & Telescope

    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). 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 is lost in the glare of the Sun.

    Venus (magnitude –3.8) is gaining altitude very gradually, low in the west-northwest in evening twilight.

    Mars and Jupiter are hidden in the glow of sunrise.

    Saturn (magnitude +0.5, at the Virgo-Libra border) glows in the southwest after dark with slightly dimmer Spica 12° to its lower right. Look about equally far to Saturn's left for Alpha Librae.

    See our telescopic guide "Scrutinizing Saturn" in the May Sky & Telescope, page 50, or the shorter version on our website. Identify Saturn's many moons at any time and date with our SaturnMoons utility or handier app.

    Uranus (magnitude 5.8 in Pisces) and Neptune (magnitude 7.9 in Aquarius) are high in the southeast before the beginning of dawn. 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.


    Like This Week's Sky at a Glance? Watch our SkyWeek TV short, also playing on PBS.


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