Venus with Castor and Pollux at dusk, early June 2018
Venus poses with Castor and Pollux in the west as twilight deepens. The brilliant planet will line up with the two stars on June 10th and 11th. (The scene is oriented for a skywatcher near 40° north latitude.)

Friday, June 8

Double stars in Lyra. Vega is the brightest star very high in the east after dark. Just lower left of it is 4th-magnitude Epsilon Lyrae, the Double-Double. Epsilon forms one corner of a roughly equilateral triangle with Vega and Zeta Lyrae. The triangle is less than 2° on a side, hardly the width of your thumb at arm's length.

Binoculars easily resolve Epsilon. And a 4-inch telescope at 100× or more should resolve each of Epsilon's wide components into a tight pair.

Zeta Lyrae is also a double star for binoculars; much tougher, but plainly resolved in any telescope.

Delta Lyrae, below Zeta, is a much wider and easier pair. Notice its colors.

Saturday, June 9

• For much of the spring at mid-northern latitudes, the Milky Way lies right down out of sight all around the horizon. But watch the east now. The rich Cepheus-Cygnus-Aquila stretch of the Milky Way is rising up all across the east late these nights, earlier and higher every week. A hint for the light-polluted: It runs horizontally under Vega, right through the Summer Triangle.

Sunday, June 10

• In twilight this evening and tomorrow evening, Venus in the west almost perfectly lines up with Pollux and Castor to its right. The two stars come into view as night approaches, long after Venus is easy.

Monday, June 11

• Spot the Big Dipper very high in the northwest after dark. The middle star of its bent handle is Mizar, with tiny little Alcor right next to it. On which side of Mizar should you look for Alcor? As always, on the side toward Vega! Which is now the brightest star in the east.

Tuesday, June 12

• The Big Dipper hangs high in the northwest as the stars come out. The Dipper's Pointers, currently its bottom two stars, point lower right toward Polaris.

Above Polaris, and looking very similar to it, is Kochab, the lip of the dim Little Dipper's bowl. Kochab stands precisely above Polaris around the end of twilight or a little after. How precisely can you time this event for your location? How fast can you see a change, perhaps using a hanging plumb bob or the vertical edge of a building?

• Explore ten fine double and multiple stars of early summer, in a wide variety, using Sue French's Deep-Sky Wonders article and finder charts in the June Sky & Telescope page 54.

Moon, Venus, Mercury, June 14-15, 2018
The thin waxing crescent Moon now adds to the interest in the western twilight. . .
Moon, Venus, Regulus, June 16-17, 2018
. . . and it continues to do so as it thickens.

Wednesday, June 13

• Bright yellow Arcturus, magnitude 0, shines high overhead toward the southwest these evenings, high to the upper right of Jupiter. The kite shape of Bootes, its constellation, extends up from Arcturus. The kite is narrow, slightly bent, and 23° tall: about two fists at arm's length.

• Just east (left) of the Bootes kite is Corona Borealis, the pretty but mostly dim Northern Crown. Get to know its half-circle of stars with Matt Wedel's Binocular Highlight column and chart in the June Sky & Telescope, page 22.

• New Moon (exact at 3:43 p.m. EDT).

Thursday, June 14

• Can you see Mercury after sunset yet? Use the Venus and the Moon to guide you to it using the chart at right. Note: The visibility of objects in bright twilight is exaggerated here.

Action at Jupiter: Io disappears behind Jupiter's western limb tonight at 11:16 p.m. EDT, followed by Ganymede at 11:55 p.m. EDT. Then Ganymede reappears from behind Jupiter's eastern limb at 1:32 a.m. EDT. Io reappears out of eclipse by Jupiter's shadow just off the planet's eastern limb at 2:15 a.m. EDT.

And by that time, the Great Red Spot should be 40 minutes from crossing Jupiter's central meridian.

For all such events at Jupiter this month, for all time zones worldwide, see the tables in the June Sky & Telescope, pages 50-51.

Friday, June 15

• Here it is almost summer. But as twilight fades, look very low in the north-northwest for wintry Capella very out of season. The farther north you are, the higher it will appear. You may need binoculars. If you're as far north as Portland Oregon and Portland Maine, Capella is actually circumpolar.

Saturday, June 16

• Look low in the west as twilight fades for Venus and the thin waxing crescent Moon, as shown here. They're about 8° apart at the times of twilight for North America. Higher to their upper left, look for much fainter Regulus as twilight fades further.


Want to become a better 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.

Pocket Sky Atlas, jumbo edition
The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and hundreds of telescopic galaxies, star clusters, and nebulae among them. Shown above is the Jumbo Edition for easier reading in the night. Larger view. Sample chart.

Once you get a telescope, to put it to good use you'll need a detailed, large-scale sky atlas (set of charts). The basic standard is the Pocket Sky Atlas (in either the original or Jumbo Edition), which shows stars to magnitude 7.6.

Next up is the larger and deeper Sky Atlas 2000.0, plotting stars to magnitude 8.5; nearly three times as many. The next up, once you know your way around, is 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, or the bigger Night Sky Observer's Guide by Kepple and Sanner.

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 (meaning heavy and expensive). And 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

Mars on June 5, 2018
Mars on June 5th, when it was 16.1 arcseconds wide and showing a bright dust storm. Damian Peach took this series of images using the 1-meter Chilescope remotely in poor seeing. North is up here, which means Mars is rotating to the right. The second image was taken 3 hours 20 minutes after the first, and the third 30 minutes after the second. Big, dark Syrtis Major rotates away from the central meridian to the sunset terminator near the preceding limb, while the Sinus Sabaeus – Sinus Meridiani complex comes around to take its place front and center. The bright area just left of Sinus Meridiani is a new dust storm obscuring a large area of Oxia Palus and Margaritifer Sinus. UPDATE: The dust storm had ballooned enormously by June 8th, engulfing the Opportunity rover still active on Sinus Meridiani.
Mercury on April 27, 2018
Who says details on Mercury can't be recorded reliably from Earth? Mercury just had a very poor dawn apparition for the Northern Hemisphere, but from the southern latitude of the 1-meter Chilescope, the apparition was excellent. Damian Peach used the telescope remotely to take this stacked-video image at sunrise on April 27th. North is up.
Jupiter with Great Red Spot on May 1, 2018
Jupiter's Great Red Spot side on May 1st . . .
Jupiter on May 23, 2018
. . . and on May 23rd. South is up. Like a white snake with a giant red eye chasing its tail around the planet, a strong white band in the South Tropical Zone extends from the Great Red Spot westward (preceding; left here) almost all the way around to the snake's nose. In this three-week span, the nose nearly caught up to the tail. Will this continue until they merge? Christopher Go in the Philippines has long been imaging Jupiter with his 14-inch scope.

Mercury is pretty well hidden down in the sunset. Next week it'll be coming up into view.

Venus (magnitude –4.0, crossing from Gemini into Cancer) shines brightly in the west-northwest during twilight and just after. In a telescope (look early: as soon after sunset as you can pick it up) Venus is a gibbous disk 14 arcseconds wide and 77% sunlit.

Mars (magnitude –1.4, in Capricornus) rises around 11 or midnight daylight-saving time. Watch for it to come up about 30° lower left of Saturn. Mars is highest in the south, in best view for telescopes, just before dawn.

Mars is enlarging and brightening on its way to an unusually close opposition at the end of July. It's now 17 arcseconds wide — bigger than at some of its oppositions! It will grow to 24.3 arcseconds for the week around its closest approach on the night of July 30–31.

See our telescopic guide to Mars in the July Sky & Telescope, page 22. You'll also want a Mars map that shows which features are facing Earth at your time and date, such as our Mars Profiler online.

Vesta, the brightest asteroid, is having an unusually close and bright apparition in the Ophiuchus Milky Way a little north of Saturn and near the open star cluster M23. It's now magnitude 5.4 and will be 5.3 around its June 19th opposition. Article and finder charts: Vesta Gets Close and Bright.

Jupiter (magnitude –2.5, in Libra) shines in the south-southeast as twilight fades. It's highest in the south shortly after dark and still 44 or 43 arcseconds in equatorial diameter. See our telescopic guide to observing Jupiter in the May Sky & Telescope, page 48.

Jupiter remains only 1° or 1½° from 3rd-magnitude Alpha Librae (Zubenelgenubi), a fine, wide double star for binoculars. The star's two components, magnitudes 2.8 and 5.1, are a generous 231 arcseconds apart. Nevertheless they form a true, gravitationally bound pair; they're both 77 light-years away and are creeping in tandem across the sky (common proper motion). They're bigger and brighter than our Sun, shining with 36 and 4 times the Sun's light.

And check in on Jupiter's moons in binoculars. They're tiny points lined up closely east and west of the planet, changing position every night. The higher your binoculars' magnification the better for them.

Saturn (magnitude +0.1, just above the Sagittarius Teapot) rises in the southeast in twilight. It stands highest in the south around 2 a.m., about 30° to the right of much brighter Mars.

Uranus is barely emerging from the glow of dawn.

Neptune (magnitude 7.9, in Aquarius) is up in the east-southeast before the beginning of dawn. Finder chart.


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) is Universal Time (also called UT, UTC, GMT, or Z time) minus 4 hours.


"Remember to look up at the stars and not down at your feet. Try to make sense of what you see and wonder about what makes the universe exist. Be curious."
— Stephen Hawking, 1942–2018


"The dangers of not thinking clearly are much greater now than ever before. It's not that there's something new in our way of thinking, it's that credulous and confused thinking can be much more lethal in ways it was never before."
— Carl Sagan, 1996


"Objective reality exists. Facts are often determinable. Vaccines save lives. Carbon dioxide warms the globe. Bacteria evolve to thwart antibiotics, because evolution. Science and reason are not a political conspiracy. They are how we determine facts. Civilization's survival depends on our ability, and willingness, to do so."
— Alan MacRobert, your Sky at a Glance editor


"Facts are stubborn things."
— John Adams, 1770



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