This Week’s Sky at a Look, July three – 13

July 3, 2019 - Comment

Further lengthy “week” of listings this week, ‘trigger we’re away July 4th! Because the waxing crescent Moon returns to the night sky, it passes the troublesome Mercury-Mars-Pollux-Castor lineup. (The visibility of faint objects in vibrant twilight is exaggerated right here.) Then on the fifth and sixth, the thicker Moon passes beneath Leo larger up. (The

Further lengthy “week” of listings this week, ‘trigger we’re away July 4th!

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

Because the waxing crescent Moon returns to the night sky, it passes the troublesome Mercury-Mars-Pollux-Castor lineup. (The visibility of faint objects in vibrant twilight is exaggerated right here.)

Moon under Leo, July 5-6, 2019

Then on the fifth and sixth, the thicker Moon passes beneath Leo larger up. (The blue 10° scale is concerning the dimension of your fist at arm’s size.)

Wednesday, July three

• Arcturus, the sensible yellow-orange star excessive within the southwest after darkish, is the main mild of Bootes the Cowherd. The constellation’s brightest stars type a kite form extending up from Arcturus. The kite is somewhat slim, bent a bit left on the high, and 23° tall: about two fists at arm’s size. Arcturus is the slim backside level the place the kite’s quick little tail is tied on, fluttering towards the decrease proper.

Thursday, July four

• Whereas night twilight remains to be pretty vibrant, the skinny waxing crescent Moon guides the best way to the low line of Mercury, Mars, Pollux, and Castor disappearing into the sundown, as proven within the high panel. Carry binoculars!

• Earth is at aphelion, its farthest from the Solar for the 12 months. We’re three.three% farther from the Solar than at perihelion in January.

Friday, July 5

• As twilight fades, search for Regulus to emerge into view 2° or three° from the crescent Moon, as proven right here (for the center of North America).

Saturday, July 6

• Three doubles on the high of Scorpius. The pinnacle of Scorpius — the vertical row of three stars to the correct of Jupiter and Antares — is highest within the south after darkish this week. The brightest of the three is Delta (δ) Scorpii, the one within the center.

The highest star of the row is Beta (ß) Scorpii, a high quality double star for telescopes.

Simply 1° beneath Beta is the very broad naked-eye pair Omega1 and Omega2 Scorpii, not fairly vertical. Binoculars present their slight shade distinction. They’re spectral sorts B9 and G2.

Left of Beta by 1.6° is Nu Scorpii, one other high quality telescopic double. Or somewhat triple. Excessive energy in good seeing reveals that Nu’s brighter part itself is an in depth binary, separation 2 arcseconds.

Sunday, July 7

• Excessive within the northwest after darkish, the Massive Dipper hangs down by its deal with because it begins its lengthy, gradual scoop towards the correct.

• Low within the north-northeast, in the meantime, the upright W of Cassiopeia is slowly starting to tilt and climb.

Monday, July eight

• First-quarter Moon tonight (precisely so at 6:55 a.m. Tuesday morning EDT). As the celebs come out, search for Arcturus almost 30° (about three fists at arm’s size) above the Moon, and Spica lower than half that far to the Moon’s left.

• How outdated are the craters you see on the Moon with a small scope? Vivid, splashy Tycho is younger at age 85 million years. The lava-flooded craters in and across the edges of the maria clearly predate the maria, most of which flowed onto the lunar floor between three and three.5 billion years in the past. Discover the ages of many telescopic favorites with Charles Wooden’s “How Previous Is That Crater?” within the July Sky & Telescope, web page 52.

Tuesday, July 9

• Now Spica shines beneath the Moon throughout and after nightfall.

• Saturn is at opposition, shining higher left of the Sagittarius Teapot late these evenings at magnitude +zero.1. This week it is highest within the south for greatest telescopic viewing from about midnight to 2 a.m. daylight-saving time.

Wednesday, July 10

• After dusk, Altair shines within the east-southeast. It is the second-brightest star on the japanese aspect of the sky, after Vega excessive to its higher left. (Jupiter and Saturn do not depend.)

Above Altair by a finger-width at arm’s size is little orange Tarazed. A bit greater than a fist-width to Altair’s decrease left is little Delphinus, the Dolphin, leaping leftward.

Thursday, July 11

• One hour after sundown, as twilight is fading and the celebs are popping out, you may discover the 2 brightest stars of summer time, Vega and Arcturus, equally close to the zenith: Vega towards the east, Arcturus towards the southwest (relying in your location).

Moon, Jupiter, Saturn, July 12-16, 2019

Because the gibbous Moon waxes to full this month it steps above Scorpius and Sagittarius, pairing with Jupiter and Saturn alongside the best way.

Friday, July 12

• The Moon this night kinds a triangle with Jupiter to its decrease left and Antares beneath it, as proven above.

Saturday, July 13

• The Moon and Jupiter cross the sky collectively tonight, as proven above. Jupiter is the truth is 1,700 instances farther away at this month’s Moon-Jupiter pairup — and it is 40 instances bigger. The truth is the Moon is roughly the scale of Jupiter’s personal 4 Galilean moons, mere pinpoints in good, steadily braced binoculars or a small scope. This night for North America, all 4 seem on Jupiter’s celestial west aspect comparatively near the planet.


Need to change into a greater astronomer? Study your means across the constellations. They’re the important thing to finding every thing fainter and deeper to hunt with binoculars or a telescope.

That is an out of doors nature pastime. For an easy-to-use constellation information overlaying the entire night sky, use the large month-to-month map within the heart of every challenge of Sky & Telescope, the important information to astronomy.

Jumbo Pocket Sky Atlas cover

The Pocket Sky Atlas plots 30,796 stars to magnitude 7.6, and lots of of telescopic galaxies, star clusters, and nebulae amongst them. Proven above is the Jumbo Version for simpler studying within the night time. Pattern chart.

When you get a telescope, to place it to good use you may want an in depth, large-scale sky atlas (set of charts). The essential customary is the Pocket Sky Atlas (in both the unique or Jumbo Version), which exhibits stars to magnitude 7.6.

Subsequent up is the bigger and deeper Sky Atlas, plotting stars to magnitude eight.5; almost thrice as many. The following up, as soon as your means round, are the even bigger Interstellarum atlas (stars to magnitude 9.5) and Uranometria (stars to magnitude 9.75). And skim methods to use sky charts with a telescope.

You will additionally need a good deep-sky guidebook, akin to Sue French’s Deep-Sky Wonders assortment (which incorporates its personal charts), Sky Atlas Companion by Sturdy and Sinnott, or the larger Evening Sky Observer’s Information by Kepple and Sanner.

Can a computerized telescope exchange charts? Not for newcomers, I do not suppose, and never on mounts and tripods which are lower than top-quality mechanically (that means heavy and costly). And as Terence Dickinson and Alan Dyer say of their Yard Astronomer’s Information, “A full appreciation of the universe can’t come with out growing the abilities to seek out issues within the sky and understanding how the sky works. This information comes solely by spending time beneath the celebs with star maps in hand.”

This Week’s Planet Roundup

Mercury and Mars disappear into the sundown.

Venus (magnitude – stays very low in vibrant daybreak. You possibly can seek for it barely above a flat east-northeast horizon about 20 minutes earlier than dawn. Carry binoculars. Good luck.

Jupiter with Red Spot on July 2, 2019

Jupiter’s Nice Purple Spot appears fairly regular visually, however look nearer at this high-res picture taken July 2nd by Christopher Go. South right here is up. Observe the small extensions on the spot’s previous [left] and south following [upper right] sides, as Go remarks. And, “Observe the flake exercise on the next aspect of the GRS.”

Jupiter (magnitude –2.6, in southern Ophiuchus) is the white level obtrusive within the south-southeast as the celebs come out. Orange Antares, fainter at magnitude, twinkles 7° or eight° to its decrease proper. Jupiter is at its highest within the south quickly after darkish.

Jupiter and Antares type a large, flat, nearly isosceles triangle with Delta Scorpii (Dschubba) to their proper. Delta, a long-term eruptive variable of the Gamma Cassiopeiae sort, has been not a lot fainter than Antares for many of the final 19 years after, with out warning, brightening by half in July 2000.

In a telescope Jupiter is 45 arcseconds broad. See Bob King’s observing information to Jupiter.

Saturn (magnitude +zero.1, in Sagittarius) involves opposition on July ninth. It is the regular, pale yellowish “star” low within the southeast after darkish, about 30° east (decrease left) of Jupiter. Look to its decrease proper for the Sagittarius Teapot.

With a telescope you may need to observe Saturn when it is highest — from about midnight to 2 a.m. daylight-saving time — because it’s nonetheless far south this 12 months (declination –22° now) and thus by no means very excessive for us northerners. Saturn’s rings are tilted a large 23° to our line of sight, almost as open as they have been in the previous few years.

Uranus (magnitude 5.eight, in Aries) is within the east simply earlier than the primary signal of daybreak.

Neptune (magnitude 7.9, in Aquarius) is excessive within the south-southeast at the moment. Finder charts for Uranus and Neptune.


All descriptions that relate to your horizon — together with the phrases up, down, proper, and left — are written for the world’s mid-northern latitudes. Descriptions that additionally rely upon longitude (primarily Moon positions) are for North America.

Jap Daylight Time (EDT) is Common Time (UT, UTC, GMT, or Z time) minus four hours.


Audio sky tour. Out beneath the night sky along with your earbuds in place, hearken to Kelly Beatty’s month-to-month podcast tour of the heavens above. It is free.


“This journey is made attainable by generations of searchers strictly adhering to a easy algorithm. Check concepts by experiments and observations. Construct on these concepts that go the check. Reject those that fail. Comply with the proof wherever it leads, and query every thing. Settle for these phrases, and the cosmos is yours.”
— Neil deGrasse Tyson, 2014



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