Sky at a Glance | June 12th, 2009

Some daily events in the changing sky for June 12 – 20.

Friday, June 12

  • After midnight tonight, look lower left of the waning Moon in the east for Jupiter on the rise, as shown at right. They stand high in the south-southeast by dawn.

    Saturday, June 13

  • As twilight fades this week, look low in the northwest for bright Capella. See how it twinkles at such a low altitude! Binoculars may show it flashing vivid colors as it very slowly sinks.

    How late in the season can you continue to see Capella? This depends entirely on your latitude. North of latitude 46° (Seattle, Quebec City, central France) the star is circumpolar and never sets at all.

    Sunday, June 14

  • With summer soon to begin, the Big Dipper this week hangs straight down by its handle high in the northwest after dark.

    Monday, June 15

  • Last-quarter Moon (exact at 6:15 p.m. EDT).

    Tuesday, June 16

  • Have you checked in on Gamma Virginis yet this year? This widening double star (also known as Porrima), shining at 3rd magnitude in Virgo, is now split by 1.3 arcseconds after being unresolvably close at periastron four years ago. I can now distinguish the two identical stars in my 6-inch scope at 200×, given steady seeing, and very easily in my 12.5-inch. See the June Sky & Telescope, page 54.

    Wednesday, June 17

  • You can spend all evening for nights on end exploring the galaxies of Canes Venatici, the Hunting Dogs, behind the Big Dipper's handle. See Sue French's "Deep-Sky Wonders" column and chart in the June Sky & Telescope, page 56. (On the photo on page 57, move the "NGC 5355" label to the galaxy that's labeled "5358".)

    Thursday, June 18

  • During dawn Friday morning the crescent Moon hangs about 6° above Venus and Mars (for North America), as shown below.

    Friday, June 19

  • A small telescope will almost always show Titan, Saturn's largest moon. Tonight Titan is four ring-lengths to Saturn's west. A guide to identifying other satellites of Saturn and Jupiter for amateur scopes is in the June issue of Sky & Telescope, page 47.

    Saturday, June 20

  • Tonight is the shortest night of the year (for the Northern Hemisphere); the solstice is at 1:46 a.m. on the 21st EDT, marking the start of summer. Paradoxically, this is called "Midsummer" Night — traditionally a time of all-night bonfires and partying, when the veil between our world and the world of elves and fairies was supposed to be unusually thin.

    Moon and three planets at dawn
    Look early in the dawn to catch Venus and Mars at their closest this week and next.
  • To end Midsummer Night, busy things are happening at dawn Sunday morning the 21st! About 45 minutes before your local sunrise, clear the bonfire smoke from your eyes and spot bright Venus in the east with faint little Mars just to its upper left. Using binoculars, look well left of Venus for the Pleiades, and look about 24° to Venus's lower left to pick up the thin crescent Moon and (lower right of the Moon for North America) Mercury.

    Mercury this morning is in turn just 0.2° from Epsilon Tauri, magnitude +3.5, in the Hyades. Will binoculars show this star? It marks the upper tip of the "V" shape of the Hyades emerging from the sunrise. First-magnitude Aldebaran 3° below marks the Hyades' southern tip. See the illustration at right.

    Rouse other members of the party to take a look. Welcome to summer.


    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 each issue of Sky & Telescope, the essential magazine of astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).

    Sky Atlas 2000.0 (the color Deluxe Edition is shown here) plots 81,312 stars to magnitude 8.5. That includes most of the stars that you can see in a good finderscope, and typically one or two stars that will fall within a 50× telescope's field of view wherever you point. About 2,700 deep-sky objects to hunt are plotted among the stars.
    Alan MacRobert
    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
    Sky Atlas 2000.0 or the smaller Pocket Sky Atlas) and good deep-sky guidebooks (such as Sky Atlas 2000.0 Companion by Strong and Sinnott, the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic Burnham's Celestial Handbook). Read how to use them effectively.

    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 and a curious mind." Without these, "the sky never becomes a friendly place."

    More beginners' tips: "How to Start Right in Astronomy".


    This Week's Planet Roundup

    Jupiter on June 17, 2009
    Jupiter's Great Red Spot (GRS) is pale this year, and the South Equatorial Belt, which the Red Spot sits in, looks pretty quiet. But the North Equatorial Belt (NEB, below center) is going nuts! In the parts of the NEB north of the Great Red Spot, the prominent white swirls of three weeks ago have morphed into dark chaos. Also note the very long, straight, diagonal red-brown line crossing the NEB.

    Christopher Go took this image at 17:54 UT June 17, 2009, when the central-meridian longitude (System II) was 150°. South is up.


    For all of the Red Spot's central-meridian crossing times, good worldwide, use our Red Spot calculator or print out our list for 2009.

    Mercury (about magnitude 0) is having a poor apparition deep in the glow of dawn. Look for it in morning twilight about 23° lower left of Venus. Binoculars will help.

    Venus and Mars (magnitudes –4.4 and +1.1, respectively) remain together due east during dawn. Venus is a dazzler; Mars is 150 times fainter. Look for Mars to Venus's left or upper left by only 3° or 2° this week, hardly more than a finger's width at arm's length. They're in conjunction, 2.0° apart, on the morning of June 22nd.

    Four reasons combine to create their great disparity in brightness. Mars is farther from the Sun so it's illuminated less brightly than Venus, Mars is a smaller planet, its surface is darker and less reflective than Venus's white clouds, and it's currently farther from Earth.

    Jupiter (magnitude –2.5, in Capricornus) now rises before midnight and shines brightly in the south by dawn. The sharpest telescopic glimpses may come during morning twilight, when the atmospheric seeing sometimes turns very steady.

    Dim-ringed Saturn on June 16, 2009
    On June 16th Saturn's rings were still tipped 3.7° to our line of sight, but they were tipped a mere 0.8° to the incoming sunlight. All year the rings' tilt to the Sun has been steadily decreasing, and accordingly, the rings have been getting darker and darker. Keep watch! Saturn is becoming harder to observe as it moves lower in the west each evening.


    S&T's Sean Walker took this stacked-video image using a 14-inch Schmidt-Cassegrain scope at f/22, a DMK21AU04.AS camera, and Custom Scientific RGB filters.

    S&T: Sean Walker
    Saturn (magnitude +1.0, in Leo) is in the southwest at dusk and sinks lower in the west as the evening advances. In a telescope Saturn's rings are beginning to narrow again, appearing only about 3.5° from edge on. And see how they're dimming! The caption at right tells why.

    Uranus (magnitude 5.9, in Pisces) is between Venus and Jupiter before dawn.

    Neptune (magnitude 7.9, in Capricornus) appears only 3/4° from Jupiter, but it's 15,000 times fainter. See our finder charts for Uranus and Neptune.

    Pluto (14th magnitude, in northwestern Sagittarius) is highest in the south around 1 a.m. See the finder chart in the June Sky & Telescope, page 53.

    All descriptions that relate to your horizon or zenith — 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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