This Week’s Sky at a Glance, June 9 – 17

 

Moon and Saturn, June 9, 2017

Saturn and the Moon are both close to the opposition point in the sky on Friday night June 9th.

Friday, June 9

• This evening, look for Saturn a few degrees to the right of the just-past-full Moon. This is a "minimoon": it's currently near apogee. Can you really see that the Moon is a just a bit smaller than usual?

Watch it pull a bit farther away from Saturn as they cross the sky together through the night.

The full Moon of June is traditionally called the Strawberry Moon or . . . (wait for it . . .) the Honey Moon. Perhaps because it rides low across the sky, where summer haze may turn it honey-yellow all night.

Saturday, June 10

• With summer officially just 11 days away, the Summer Triangle stands 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 a greater distance to Vega's lower right.

Sunday, June 11

• A small telescope will show Jupiter's moon Io reappearing out of eclipse from Jupiter's shadow around 11:32 p.m. Eastern Daylight Time. Watch for it to gradually emerge into view just east of the planet.

Monday, 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 Little Dipper's bowl.

Kochab stands precisely above Polaris around the end of twilight or a little after. How well can you time this event for your location? How fast can you see any tilt with respect to a hanging plumb bob or the vertical edge of a building?

Epsilon in Lyra

Epsilon Lyrae, the famous "Double-Double," is resolved in this photo. Zeta Lyrae, below it where lines meet, is not. Next lower left from Zeta is Delta, a very wide binocular pair. Seen in the sky these evenings, Lyra is rotated counterclockwise somewhat compared to this. Bob King photo.

Tuesday, June 13

• After dark, Vega is the brightest star very high in the east. Just lower left of it (or upper left in this photo) 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.

• On Wednesday morning, the Sun rises its earliest of the year if you're near 40° north latitude. The summer solstice comes seven days later.

Wednesday, June 14

• Saturn is at opposition tonight. For just a few days around opposition, Saturn's rings turn a little brighter than usual with respect to Saturn's globe, a phenomenon called the Seeliger effect. It's caused by ring particles backscattering sunlight toward the Sun (and, right now, Earth).

Thursday, June 15

• With June halfway through, the Big Dipper has swung around to hang down by its handle high in the northwest during evening. The middle star of its handle is Mizar, with tiny Alcor right next to it. On which side of Mizar should you look for Alcor? As always, on the side toward Vega! Which now is shining high in the eastern sky.

Friday, June 16

• By the time it's fully dark this week, Altair is shining well up in the east. A finger-width above it or to its upper left is its little sidekick Tarazed (Gamma Aquilae), actually an orange giant that's far in the background. Altair is 17 light-years from us; Tarazed is about 460.

Saturday, June 17

• The last-quarter Moon rises late tonight, around 1 a.m. daylight-saving time. Watch for it to breach the horizon to the lower right of the Great Square of Pegasus.

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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 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 — which may sound like a lot, but it's less than one per square degree on the sky. Also plotted are many hundreds of telescopic galaxies, star clusters, and nebulae. 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

Jupiter on June 1, 2017

The non-Red-Spot side of Jupiter on June 1st, imaged by Christopher Go in the Philippines. South is up.

Mercury is lost in the sunrise.

Venus (magnitude –4.4) shines in the east during dawn. A telescope shows it barely on the gibbous side of dichotomy (half-lit phase).

Mars is lost in the sunset.

Jupiter (magnitude –2.2, in Virgo) shines high and bright in the southwest during evening. No other point in the evening sky is so bright. Spica, magnitude +1.0 and noticeably bluer, glitters 11° left of it. In a telescope, Jupiter has shrunk to 40 arcseconds wide.

Saturn (magnitude 0.0, in southern Ophiuchus) reaches opposition on the night of June 14–15. It glows low in the southeast at nightfall, 16° lower left of twinklier Antares. Not until after midnight is Saturn highest in the south.

Uranus (magnitude 5.9, in Pisces) is low in the glow of dawn.

Neptune (magnitude 7.9, in Aquarius) is well up in the southeast before the first light of dawn.

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

Eastern Daylight Time (EDT) is Universal Time (UT, UTC, or GMT) minus 4 hours.

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"This adventure is made possible by generations of searchers strictly adhering to a simple set of rules. Test ideas by experiments and observations. Build on those ideas that pass the test. Reject the ones that fail. Follow the evidence wherever it leads, and question everything. Accept these terms, and the cosmos is yours."
— Neil deGrasse Tyson, 2014


"Objective reality exists. Facts are often determinable. Vaccines do stop diseases. Carbon dioxide does warm the globe. Science and reason are no political conspiracy; they are how we discover reality. Civilization's survival depends on our ability, and willingness, to do so."
— Alan MacRobert, your Sky at a Glance editor


"Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts and evidence."
— John Adams, 1770


 

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