This Week’s Sky at a Glance

Friday, July 5

  • Venus, the "Evening Star," is very gradually brightening and moving higher above the west-northwest horizon in twilight. Keep watch through the summer and fall!

    A very thin waning Moon hangs low in bright dawn on Saturday morning the 6th, amid other low sights. Bring binoculars.
  • During dawn 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 (only 1/30 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, balanced on its bottom corner.

    Sunday, July 7

  • When the stars begin to come out these evenings, the Big Dipper hangs straight down from its handle high in the northwest, while the dim, elusive Little Dipper stands straight up on its handle from Polaris in the north.

    Monday, July 8

  • This is the time of year when, as twilight fades to dark, the two brightest summer stars, Arcturus and Vega, shine equally close to the zenith (depending on where you are). Arcturus is the one toward the southwest; Vega is toward the east.

  • New Moon (exact at 3:14 a.m. on this date EDT).

    Tuesday, July 9

  • If you have a dark enough sky, the Milky Way forms a magnificent arch high across the eastern sky after nightfall. It runs all the way from below Cassiopeia 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.

    Wednesday, July 10

  • Soon after sunset while the sky is still bright, watch for the thin crescent Moon coming into view just above the west horizon, to the lower left of Venus. Binoculars help.

    The Moon comes back to join Venus under looming Leo after sunset. (Moon positions are exact for the middle of North America.)

    Thursday, July 11

  • As twilight fades, spot the crescent Moon low in the west. Venus is roughly 1½ fist-widths at arm's length to its right (for North America). As dusk deepens, watch for Regulus and Gamma (γ) Leonis coming into view above them, as shown at right.

    Friday, July 12

  • The crescent Moon, faint Regulus, and bright Venus form a curving line low in the western twilight, as shown at right.

    Saturday, July 13

  • This is the time of year when Scorpius stands highest in the south right after dark — especially its Milky-Way-crossed southern part, rich in bright deep-sky objects. The bright upper-right part of Scorpius includes orange Antares and, to Antares's right, Delta Scorpii, a star that 13 years ago doubled in brightness and still rivals Antares for attention.


    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).

    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

    Double-shadowed Saturn. Saturn is near eastern quadrature during July and August (90° east of the Sun), so this is when its globe casts the widest shadow onto the rings behind, as seen from Earth's viewpoint. That's the black band on the rings just off the globe at lower right of center (celestial northeast).

    Meanwhile, the rings are now casting an almost equally prominent shadow onto the globe. That's the black rim above the rings (south here is up). Both add to Saturn's 3-D appearance in a telescope.

    The gray band on the globe just inside the rings is the semitransparent C Ring, the sparse "Crepe Ring," with no shadow currently behind it to confuse its appearance.

    Damian Peach shot this extraordinarily fine image through excellent seeing conditions on July 8th.


    Mercury is hidden in the glare of the Sun.

    Venus (magnitude –3.9) is gradually gaining altitude, shining brightly low in the west-northwest in evening twilight. In a telescope it's still quite small (11 arcseconds) and gibbous (89% sunlit). But for the rest of the year, watch it grow in size and wane in phase until becoming a long, ultra-thin crescent.

    Mars and Jupiter are deep in the glow of dawn.

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

    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.

    No, we don't call Pluto a planet, but if you've got a large telescope and think you can try for this 14th-magnitude speck in Sagittarius, use the big finder chart in the June Sky & Telescope, page 52. Pluto was at opposition July 2nd.


    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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