This Week’s Sky at a Glance, June 19 – 27

Some daily sky sights among the ever-changing Moon, planets, and stars.


Venus and Jupiter are approaching conjunction.

Don't miss the twilight sky show now going on in the west! (The shape of the triangle the Moon forms with the planets each evening will differ somewhat from this for viewers far from the middle of North America.)

Friday, June 19

The pair-up of Venus and Jupiter is becoming ever more eye-catching in the west at dusk, as they near their June 30th closest approach. This evening as twilight fades, look below them for the thin waxing crescent Moon, as shown here.

Saturday, June 20

The Moon, Jupiter, and Venus form a striking triangle in the west during and after dusk. Regulus and the Sickle of Leo watch over them from the upper left. Think photo opportunity!

Sunday, June 21

Now the Moon shines left of Regulus in the evening. Jupiter and Venus are farther lower right, as shown here.

Today is the longest day of the year in the Northern Hemisphere; the shortest in the Southern Hemisphere. The solstice is at 12:38 p.m. EDT (16:38 UT), marking the official start of northern summer (southern winter). Because the solstice time falls right between the nights before and after in the Eastern time zone, you can have two Midsummer's Night parties!

Monday, June 22

Saturn is the brightest point glowing in the south these evenings. The stars of upper Scorpius glitter below and lower left of it.

Tuesday, June 23

As night falls, look for the Big Dipper hanging straight down in the northwest. Its bottom two stars, the Pointers, point to the right toward modest Polaris, the handle-end of the Little Dipper. Most of the Little Dipper is very dim. This is the time of year when it floats straight upward from Polaris when nightfall is complete — like a helium balloon escaped from some June evening party.

Wednesday, June 24

The Summer Triangle looms high 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.

First-quarter Moon (exact at 7:02 a.m. EDT).

Thursday, June 25

Look for pale bluish Spica below the Moon this evening. Four-star Corvus is much farther below them and perhaps a bit right.

The brightest star shining very high above the Moon is Arcturus.

Friday, June 26

Venus and Jupiter, shining in the west as twilight fades, are now only 2.2° apart! That's about the width of your thumb held at arm's length. They point to fainter Regulus, twinkling to their upper left. Watch the two planets move closer together each evening until their appulse (closest approach) on Tuesday June 30th. That evening they'll be just 1/3° apart, seven times closer than they appear now!

In reality, they're not close together at all. Venus is 51 million miles from Earth this evening; Jupiter is eleven times farther at 561 million miles.

Saturday, June 27

Venus and Jupiter have closed to 1.7° from each other in the west at dusk.

In the southern sky, look for Saturn lower left of the gibbous Moon this evening. Scattered to the lower left of Saturn are the stars of Scorpius. The brightest of these is orange Antares.

Look low in the east-northeast about 45 minutes before sunrise tomorrow morning to catch Mercury, as shown below. Can you also see twinkly Aldebaran?

Mercury and fainter Aldebaran now await early risers with an open view low to the east-northeast.

Mercury and fainter Aldebaran now await early risers who find an open view low to the east-northeast. Binoculars will help, especially as the sky brightens.

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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.

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 the little Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger and deeper Sky Atlas 2000.0 (stars to magnitude 8.5); and once you know your way around, 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, the bigger Night Sky Observer's Guide by Kepple and Sanner, or the beloved if dated Burnham's Celestial Handbook.

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). 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 map by Peach, March 2015

Damian Peach assembled this complete map of Jupiter from images he took in March 2015. Click here for full-size version. North is up. Among other notable features are Red Spot Junior (Oval BA) to the lower right of the Great Red Spot, eleven white ovals all at the same latitude just a bit farther south in the South Temperate Belt, and the strikingly dark red, but transient, barge in the broken North Temperate Belt. Here's a rotating Jupiter globe that Peach made from this map.

Mercury is low in the glow of sunrise. By week's end it's becoming easier to see, low in the east-northeast as shown above.

Venus and Jupiter are the two bright "stars" in the west during and after twilight. They shine at an impressive magnitude –4.5 and –1.8, respectively. They continue closing in on each other: from 7° apart on June 19th to 2° on the 26th.

They'll have a spectacularly close appulse (closest approach) on June 30th: only 1/3° apart at dusk for the time zones of the Americas. (Their actual conjunction in right ascension comes on July 1st, when they're slightly farther apart.)

Mars is hidden deep in the glare of sunrise.

Saturn (magnitude +0.2, above the head of Scorpius) is highest in the south soon after dark. About 12° lower left of Saturn twinkles fiery orange Antares, not quite as bright.

Uranus (magnitude +5.9, in Pisces) and Neptune (magnitude +7.9, in Aquarius) are well up in the east and southeast, respectively, before dawn begins to brighten. Finder charts.

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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

 


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