Sky at a Glance | June 10th, 2011

Dusk view. Twist the panel clockwise for later in the night.
Watch the thickening Moon march through the gap between Virgo and Corvus night to night.

Friday, June 10

  • Look to the upper right of the Moon this evening for Saturn and little Porrima. Upper left of the Moon is Spica. Brighter Arcturus shines very high above them all (out of the frame here).

    Saturday, June 11

  • Around 10 or 11 p.m. (depending on where you live), the dim Little Dipper floats straight upward from Polaris at the end of its handle, like a lost helium balloon trailing its string.

  • With summer almost here, the big Summer Triangle is beginning to dominate the eastern sky. Its topmost and brightest star is Vega, plain to see. Look lower left of Vega, by two or three fist-widths at arm's length, for Deneb, the brightest star in that area. Farther to Vega's lower right is Altair.

    Sunday, June 12

  • While the Little Dipper floats straight up, the Big Dipper hangs straight down. Look for the Big Dipper high in the northwest after dark this week. Its Pointer stars (currently the bottom two) point rightward toward Polaris, the bottom star of the Little Dipper's handle.

    Dusk view
    Scorpius is rearing up behind this month's nearly-full Moon.

    Monday, June 13

  • The thick gibbous Moon shines near the head of Scorpius this evening. Look for Antares farther to the Moon's lower left, as shown here.

    Tuesday, June 14

  • Look for Antares to the right of the Moon, as shown here.

    Wednesday, June 15

  • Full Moon, in Sagittarius (exactly full at 4:14 p.m. EDT). A total eclipse of the Moon is visible from Africa, Australia, much of Asia, and parts of Europe and South America. Lunar eclipse details and webcasts.

    Thursday, June 16

  • Look rather low in the west-northwest as twilight fades to find Pollux and Castor, lined up more or less horizontally. These two "winter" stars have far outstayed their season. How much longer in June can you follow them as they sink down?

    Friday, June 17

  • The Moon rises in the east-southeast in late evening, depending on where you are. Far to its upper left shines Altair. Farther on in the same direction are the other two stars of the Summer Triangle: Vega and lesser Deneb.

    Saturday, June 18

  • The two brightest stars of summer are Vega, high in the east these evenings, and Arcturus, even higher in the southwest. They're both fairly near neighbors of ours as stars go: they're 25 and 37 light-years from the solar system, respectively. But that's only part of why they appear so bright. Vega is hotter, larger, and 50 times more luminous than the Sun. Arcturus puts out 150 times the light of the Sun.


    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 magazine of 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
    must have a detailed, large-scale sky atlas (set of charts). The standards are the Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger and deeper Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts effectively.

    You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.

    Can a computerized telescope take their place? I don't think so — not for beginners, anyway, and especially not on mounts that are less than top-quality mechanically. 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."


    This Week's Planet Roundup

    Jupiter on June 8, 2011
    Jupiter is coming into better view now low in the dawn, but it's still very far from its best. Christopher Go obtained this fine stacked-video image anyway on June 8th. Jupiter's dark South Equatorial Belt (above center) has fully returned and is very wide. The narrower North Equatorial Belt remains darker red-brown, with even darker barges. At the time of the photo the Great Red Spot had just barely passed the planet's central meridian (where the System II longitude was 163°). The SEB practically encompasses the Red Spot, and the Red Spot Hollow around the spot has changed from white to dark. South is up.

    Mercury is hidden in the glare of the Sun.

    Venus (magnitude –3.8) shines barely above the east-northeast horizon as dawn grows bright. Look for it 20 or 30 minutes before sunrise.

    Mars (dim at magnitude +1.3) is low in the dawn very far to the lower left of Jupiter, but not as far as Venus. Try with binoculars.

    Jupiter (magnitude –2.2, at the Aries-Pisces border) shines in the east during dawn.

    Saturn (magnitude +0.8, in Virgo) is in fine view in the south to southwest after dusk. And just ¼° to its upper right is fainter Porrima (Gamma Virginis), turning Saturn into a naked-eye "double star." Shining 15° to Saturn's left is Spica.

    In a telescope Saturn's rings are 7.3° from edge on, their minimum tilt for more than a decade to come. The rings are casting a relatively wide, prominent black shadow southward onto the globe, and the globe's shadow on the rings is visible just off the globe's celestial east (following) side. The North Equatorial Belt is a dusky band. North of it, Saturn's seven-months-old white outbreak is still active, as shown here; read more about this huge storm as studied from the Cassini Saturn orbiter and the Very Large Telescope in Chile.

    Saturn on May 30, 2011
    Saturn's white activity continues in the planet's northern hemisphere, as seen in this image taken by Christopher Go on May 30th. South is up. This image was created from stacked, selected video frames (taken with an 11-inch scope); don't expect to see this much detail visually!
    Christopher Go

    See how many of Saturn's satellites you can identify in your scope using our Saturn's Moons tracker.

    And don't skip over Porrima — it's a fine, close telescopic binary with equal components and a current separation of 1.7 arcseconds. Use high power and hope for good seeing. See the article in the April Sky & Telescope, page 56.

    Uranus (magnitude 5.9, in western Pisces) is low in the east-southeast before the first light of dawn.

    Neptune (magnitude 7.9, in Aquarius) is in the southeast before dawn.

    Pluto (magnitude 14 in Sagittarius) is highest during early-morning hours. A big finder chart for it is in the July Sky & Telescope, page 64.


    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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