This Week’s Sky at a Glance, June 28 – July 6

Twilight planets.

On June 28th Mercury and Mars are still close together with Pollux and Castor to their upper right.

Moon and Venus at dawn, June 30 - July 1, 2019

As the month changes, the thin Moon at dawn points the way to super-low Venus.

Friday, June 28

• As evening grows late, even the lowest star of the Summer Triangle shines pretty high in the east now. That's Altair. It's a good three or four fists at arm's length below or lower right of bright Vega.

A marker for Altair is its little 3rd-magnitude buddy Tarazed (Gamma Aquilae), above or upper left of it by about a finger's width at arm's length.

Look left of Altair, by hardly more than one fist, for compact little Delphinus, the Dolphin.

And above the midpoint between Delphinus and Altair look for even smaller, dimmer Sagitta, the Arrow.

Saturday, June 29

• The Milky Way forms a magnificent arch across the eastern sky as evening grows late, if your sky is dark enough! The Milky Way runs all the way from below Cassiopeia in the north-northeast, up and across Cygnus and the Summer Triangle in the east, and down past the spout of the Sagittarius Teapot in the south-southeast, where it's brightest.

Sunday, June 30

• Can you spot the Coma Berenices star cluster with your unaided eyes? It's big but sparse and dim, high in the west after dark. To locate it find brilliant Arcturus high in the southwest, and to the right of that, the end star of the Big Dipper's handle. Take the midpoint between them, and look well down from there. The Coma Star Cluster forms a nearly equilateral triangle with those two stars.

You'll need a dark sky. The cluster is about 4° wide, about the size of a ping-pong ball held at arm's length. Its brightest stars form a tilted, upside-down letter Y.

In binoculars the cluster fills most of the field of view. So if you're expecting to look for something small, you'll miss it by looking right through it!

Monday, July 1

• Low in the north-northeast after dark, the upright W of Cassiopeia is slowly beginning to tilt and climb.

• Explore the double stars and deep-sky sights around the head of Hercules near the zenith, and trace out the little-known asterism Sudor Ophiuchi, using the July Sky & Telescope's Deep-Sky Wonders column and chart (page 54).

Tuesday, July 2

• The two brightest stars of summer, Arcturus and Vega, are about equally high overhead shortly after dark: Arcturus toward the southwest, Vega toward the east. Arcturus and Vega are 37 and 25 light-years away, respectively. They represent the two commonest types of naked-eye stars: a yellow-orange K giant and a white type-A main-sequence star. They're 150 and 50 times brighter than the Sun, respectively — which, combined with their nearness, is why they dominate the evening sky.

• New Moon (exact at 3:16 p.m. EDT). Total eclipse of the Sun for parts of the South Pacific, northern Chile, and central Argentina. Partial eclipse for most of South America and parts of Central America. Maps, details.

Moon, Mercury, Mars, Pollux, Castor very low at dusk, July 3-4, 2019

As the Moon returns to the evening sky as a waxing crescent, is passes the difficult Mercury-Mars-Pollux-Castor lineup . . .

Moon under Leo, July 5-6, 2019

. . . and then on the 5th and 6th the it passes under Leo, higher up. (The blue 10° scale is about the size of your fist held at arm's length.)

Wednesday, July 3

• Arcturus, the brilliant yellow-orange star high in the southwest after dark, is the leading light of Bootes the cowherd. The constellation's brightest stars form a kite shape extending up from Arcturus. The kite is rather narrow, bent a bit left at the top, and 23° tall: about two fists at arm's length. Arcturus is the narrow bottom point where the kite's short little tail is tied on, fluttering toward the lower right.

Thursday, July 4

• While evening twilight is still fairly bright, the thin waxing crescent Moon guides the way to the low line of Mercury, Mars, Pollux, and Castor as shown in the panel above. Bring binoculars!

Friday, July 5

• As twilight fades, look for Regulus to emerge into view 2° or 3° from the crescent Moon, as shown here (for the middle of North America).

• The Big Dipper, high in the northwest after dark, is starting to turn around to "scoop up water" through the evenings of summer and early fall.

Saturday, July 6

Three doubles at the top of Scorpius. The head of Scorpius — the vertical row of three stars to the right of Jupiter and Antares — is highest in the south after dark this week. The brightest of the three is Delta (δ) Scorpii, the one in the middle.

The top star of the row is Beta (ß) Scorpii, a fine double star for telescopes.

Just 1° below Beta is the very wide naked-eye pair Omega1 and Omega2 Scorpii, not quite vertical. Binoculars show their slight color difference. They're spectral types B9 and G2.

Left of Beta by 1.6° is Nu Scorpii, another fine telescopic double. Or rather triple. High power in good seeing reveals that Nu's brighter component itself is a close binary, separation 2 arcseconds.

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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.

Jumbo Pocket Sky Atlas cover

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. 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, are the even larger Interstellarum atlas (stars to magnitude 9.5) and 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

Mercury and Mars are getting more difficult low in the west-northwest as twilight fades. Look early in the week with binoculars about a half hour after sunset; see the top of this page.

Mercury fades from magnitude 0.8 on the June 28th to 1.5 on July 6th. Mars is magnitude 1.8, Pollux is 1.2, and Castor is 1.6.

Venus remains very low in bright dawn. Search for it just above the east-northeast horizon about 20 or 30 minutes before sunrise. Bring binoculars.

Jupiter on June 22, 2019

Jupiter's Great Red Spot seemed to have quieted down again by June 22nd, after shedding flakes of its red material earlier. Christopher Go image.

Jupiter (magnitude –2.6, in southern Ophiuchus) is the white point glaring in the south-southeast as the stars come out. Orange Antares, much fainter at magnitude +1.0, twinkles 8° or 9° to its right. Jupiter is highest in the south by about 11 or midnight daylight saving time, with Antares now to its lower right.

Jupiter and Antares form a wide, flat, almost isosceles triangle with Delta Scorpii (Dschubba) to their right. For most of the last 19 years Delta, an eruptive variable, has been only slightly fainter than Antares.

In a telescope Jupiter is still 46 or 45 arcseconds wide. See Bob King's observing guide to Jupiter.

Saturn (magnitude +0.1, in Sagittarius) is the steady, pale yellowish "star" low in the southeast after dark, 30° east (lower left) of Jupiter. Saturn comes to opposition on July 9th.

Uranus (magnitude 5.8, in Aries) is low in the east just before the first sign of dawn.

Neptune (magnitude 7.9, in Aquarius) is well up in the southeast before dawn. Finder charts for Uranus and Neptune.

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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, GMT, or Z time) minus 4 hours.

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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 heavens above. It's free.

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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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3 thoughts on “This Week’s Sky at a Glance, June 28 – July 6

  1. RodRod

    mary beth, enjoying some stargazing? Last night I was out from 2030 EDT until 0130 EDT this morning. Cool front came through on Sunday, NW winds, and low humidity, temps mid-60s and clear skies. Lovely view of the stars under the summer Milky Way. Jupiter and Saturn were great along with different globular clusters and nebula in the Milky Way. I pulled out both telescopes and burned up the night skies here 🙂 Brief summary report:
    https://1drv.ms/x/s!Ag__n9x2eoQT5m74rx_6kfzksxyH?e=6popWc

    1. mary bethmary beth

      Hi Rod! We’ve had a few good nights here. Jupiter seemed bigger and brighter than ever last night… I know that’s not true but it certainly appeared that way. Must be fantastic ti see the Milky Way…Never is that possible in Houston. Do you all have big plans for the holiday? Maybe will all get lucky and see some real shooting stars! Hope you have a safe and happy Fourth of July!

      1. RodRod

        mary beth, thanks and you enjoy the 4th of July too. No big plans for me, just some family time and my grandson is overnighting as well. T-storms are in our area now and likely the 4th too. This afternoon I watched the South American total solar eclipse, live on space.com. Starry Night and Stellarium software worked well and accurately showed the sky from the Chile location and total solar eclipse. On the 4th, I may do some clay trap shooting – celebrating Independence Day 🙂

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