This Week's Sky at a Glance, June 14 – 23

FRIDAY, JUNE 14

■ As we count down the last six days to summer, astronomically defined (the solstice is June 20th; believe it or not this is still only spring!), the Summer Triangle has climbed to stand high and proud in the east after dark.

Its top star is bright Vega. Deneb is the brightest star to Vega's lower left, by 2 or 3 fists at arm's length. Look for Altair farther to Vega's lower right. Altair is midway in brightness between Vega and Deneb.

By summer's end, the Triangle will be overhead right after dark.

SATURDAY, JUNE 15

■ When the stars come out for North America tonight, you'll find the Moon shining nearly midway between Spica to its lower left and fainter Gamma Virginis (Porrima) to its upper right; see below. Gamma Vir is a lovely, equal-brightness double star for telescopes, separation 3.4 arcseconds this year; they're slowly widening. The pair is oriented almost north-south.

SUNDAY, JUNE 16

■ In these warm late twilights, look very low in the north-northwest for wintry Capella very out of season. The farther north you are, the less low it will appear. You may need binoculars, and for the South it's just gone. But if you're as far north as Montreal or either of the Portlands (Oregon or Maine), Capella is actually circumpolar.

■ Looking higher, the Big Dipper hangs way up in the northwest as the stars come out. The Dipper's Pointers, currently its bottom two stars, point to the right toward Polaris. Above Polaris, and looking very similar to it, is Kochab, the lip of the Little Dipper's bowl; the rest of the Little Dipper is dim. Kochab stands precisely above Polaris around the end of twilight.

MONDAY, JUNE 17

■ Have you ever knowingly seen even a bit of the constellation Centaurus? Famous Alpha Centauri never gets above the horizon unless you’re as far south as San Antonio or Orlando (latitude 29° N). But fairly easy from much farther north is Theta Centauri, magnitude 2.0.

This evening the Moon makes it simple to find. Right after nightfall, look 19° (nearly two fists) straight down from the Moon. No other star in that area is quite as bright. Theta Cen is pale orange, as binoculars will confirm. It's at declination –36.5°, hardly farther south than the bottom of the Sagittarius Teapot. It's even 1° less far south than the familiar Cat's Eyes in the tail of Scorpius.

Theta Cen marks the top of the stick-figure Centaur's head. Add another constellation to your life list, at least of those where you've identified some fragment.

TUESDAY, JUNE 18

■ After nightfall is complete, Vega is the brightest star very high in the east. Barely 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 a telescope.

Delta Lyrae, below Zeta, is a much wider and easier pair, reddish orange and pale blue.

WEDNESDAY, JUNE 19

■ The waxing gibbous Moon tonight shines among the stars of upper Scorpius as shown below. Orange Antares is about 3° or 4° to the Moon's left or lower left, and Delta Scorpii, the next brightest star in the area, is a somewhat similar distance above the Moon or to its upper right. Delta is the middle star of the upper row of three in the graphic. Cover the bright Moon with your finger to get a better look at the stars around it.

THURSDAY, JUNE 20

■ Happy solstice! At 4:45 p.m. EDT this afternoon, the Sun reaches its farthest north position in Earth's sky and begins its six-month return southward. Astronomical summer begins in the Northern Hemisphere, winter in the Southern Hemisphere.

For us northerners, this is the year's longest day and shortest night.

It's also the day when (in the north temperate latitudes) the midday Sun passes the closest it ever can to being straight overhead, and thus when your shadow becomes the shortest it can ever be at your location. This happens at your local apparent [solar] noon, which is probably rather far removed from noon in your civil (clock) time.

And if you have a good west-northwest horizon (in mid-northern latitudes), mark carefully where the Sun sets. In a few days you should be able to detect that the Sun is once again starting to set a just little south (left) of that point.

FRIDAY, JUNE 21

■ Full Moon (exactly full at 9:09 p.m. EDT). After dark, cover the Moon with your finger to get a better look at the stars around it. You'll see that the Moon sits barely above the spout of the Sagittarius Teapot.

SATURDAY, JUNE 22

■ Now the Moon shines barely below the Teapot's handle through the evening hours.

SUNDAY, JUNE 23

■ Leo the Lion is mostly a constellation of late winter and spring. But he's not gone yet. As twilight ends look due west, somewhat low, for Regulus, his brightest and now lowest star: the forefoot of the lion stick figure.

The Sickle of Leo extends upper right from Regulus. The rest of the Lion's constellation figure runs for almost three fist-widths to the upper left from the Sickle, to his tail tip Denebola, the highest of his stick-figure's stars. Leo will soon be treading offstage into the sunset.

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This Week's Planet Roundup

Mars and Saturn are in nice view just before and during early dawn. The highest and easiest is Saturn in the southeast, magnitude 1.1. Its background is dim Aquarius. Find the Great Square of Pegasus two fists upper left of it, and Fomalhaut sparkling two fists to Saturn's lower right.

Look for Mars far lower left of Saturn, by a good four or five fists at arm's length. It's almost due east. Mars is magnitude 1.9. About a fist above Mars is Alpha Arietis (Hamal), magnitude 2.0.

And Jupiter is emerging into view almost three fists lower left of Mars, shining through the horizon murk at magnitude –2.0 as dawn brightens.

Mercury, Venus, and Uranus remain hidden in the Sun's glare.

Neptune, 8th magnitude in Pisces, is about 10° lower left of Saturn before dawn begins — for the pre-dawn adventurer with large binoculars or a telescope, a detailed enough finder chart showing Neptune's current location among the many similarly faint stars, and skill in using sky charts with binocs or a scope.

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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 and graphics that also depend on longitude (mainly Moon positions) are for North America.

Eastern Daylight Time (EDT) is Universal Time minus 4 hours. UT is also known as UTC, GMT, or Z time.

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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 a more detailed 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.

Once you get a telescope, to put it to good use you'll need a much more 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 all 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. (It's currently out of print.) The next up are the even larger Interstellarum atlas (stars to magnitude 9.5) or Uranometria 2000.0 (stars to mag 9.75). And read How to Use a Star Chart with a Telescope. It applies just as much to charts on your phone or tablet, the preferred versions for many observers these days, as it does to charts on paper.

You'll also want a good deep-sky guidebook. A beloved old classic is the three-volume Burnham's Celestial Handbook. An impressive more modern one is the big Night Sky Observer's Guide set (2+ volumes) by Kepple and Sanner. The top of the hill for total astro-geeks is the Annals of the Deep Sky series, currently at 10 volumes as it slowly works forward through the constellations alphabetically. So far it's only up to F.

Can computerized telescopes replace charts? Not for beginners I don't think, and not for scopes on mounts and tripods that are less than top-quality mechanically. Unless, that is, you prefer spending your time getting finicky technology to work rather than learning the sky. 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 and a curious mind." Without these, "the sky never becomes a friendly place."

If you do get a computerized scope, make sure its drives can be disengaged so you can swing it around and point it readily by hand when you want to, rather than only slowly by the electric motors (which eat batteries).

However, finding faint telescopic objects the old-fashioned way with charts isn't simple either. Learn the essential tricks at How to Use a Star Chart with a Telescope. It applies just as much to charts on a screen as on paper.

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Audio sky tour. Out under the evening sky with your
earbuds in place, listen to Kelly Beatty's monthly
podcast tour of the naked-eye heavens above. It's free.

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"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

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

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1. Why is the Moon always this phase when you see it near Spica at this time of year? Because at this time of year, Spica is still more than 90° from the Sun (132° on June 1st, 111° on the 15th). When the Moon is more than 90° from the Sun, it is gibbous (or full), because we see more than half of its globe sunlit.

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