On clear summer evenings after nightfall, the Milky Way is impressive—and well worth a trip to a dark site! Bright stars and constellations serve as a backdrop for the moon’s progress through the zodiac, culminating with a super moon on July 12 and 13.
Once the moon has departed, other stars serve as foreground for Milky Way star clouds. The Scorpion and the Archer host both the moon and the Milky Way, just not simultaneously. A long lineup of four bright planets is in good view before dawn all month. The South Delta Aquariid meteor shower reaches peak in the predawn hours of July 30.
Evening sky: At end of evening twilight in July, the two brightest stars, both of magnitude zero, are golden Arcturus, high in the west-southwest; and blue-white Vega, high in the east-northeast. A bluish first-magnitude star, Spica, appears 33 degrees to the lower left of Arcturus.
About halfway up from horizon to overhead at nightfall is a familiar group of seven stars—six of second magnitude, and one of third magnitude—the Big Dipper. Using its curved handle, “follow the arc to Arcturus and drive a spike to Spica.” Completing the Summer Triangle with Vega are two stars of first magnitude, Altair to Vega’s lower right, and Deneb to lower left.
In the southern sky at the end of evening twilight—up one hour and 40 minutes after sunset on July 16—is the first-magnitude red supergiant star Antares, heart of Scorpius, the Scorpion. This beautiful constellation is in fine display at nightfall in July. The Scorpion’s head is marked by three stars of second and third magnitude in a nearly vertical line to the right of Antares. Two third-magnitude stars close to Antares, one to the upper right and the other to the lower left, mark the “outworks of the heart.” Nine additional stars to lower left complete the curving tail of the arachnid. A prominent close pair, sometimes called the “cat’s eyes,” marks the end of the tail.
To the left of the Scorpion, eight stars of the constellation Sagittarius, the Archer, form a stick figure of a “Teapot.” Its two brightest stars, of second magnitude, mark the bottom star of its triangular spout and the top left star of its trapezoidal handle. The rest are of third magnitude. The top two stars of the spout lie on the shaft of the arrow of Sagittarius, the Archer, aimed to strike the Scorpion not far below its heart, Antares.
Sagittarius, Scorpius and the Summer Triangle figure prominently when you enjoy viewing the Milky Way. The center of our galaxy is located some 26,000 light years away, hidden behind dust clouds to the upper right of the Teapot’s spout and to the upper left of the end of the Scorpion’s tail. The naked-eye stars of those constellations are very much in the foreground!
The bright patch of Milky Way just above the spout of the Teapot, called the Large Sagittarius Star Cloud, is a portion of the central bulge of our galaxy not obscured by the dust clouds concentrated in the galactic plane. It appears as a “puff of steam” issuing out of the Teapot spout.
Another bright patch of the Milky Way is the Cygnus Star Cloud, within the Summer Triangle. Look along the neck of Cygnus, the Swan, or axis of the Northern Cross, from its center star to its southernmost, marking the head of the Swan. (Deneb, at the north end of the Cross, marks the Swan’s tail.) Binoculars easily reveal the Cygnus Star Cloud is indeed made up of large numbers of stars, some quite nearby, and others stretching ahead of us in our own local spiral arm of our rotating galaxy. The stars of the Sagittarius Star Cloud are much more distant, so are fainter and requiring larger optics to resolve.
Look adjacent to the Cygnus Star Cloud and extending southward toward the southern horizon for the Great Rift, a long lane of darkness dividing the Milky Way band into two streams. The darkness is caused not by the absence of stars, but instead by clouds of dust in the foreground absorbing the light of the stars beyond.
July opens the season for excellent viewing of the Milky Way at nightfall. Observe from a dark place far from light-polluted cities on clear nights when the moon is absent or no more than 25 percent full. The best dates this summer for Milky Way viewing from nightfall until three hours after sunset are July 1-3, July 18-Aug. 1, and Aug. 17-31.
Follow the moon in evening sky: As a result of the new moon of June 28 reaching its greatest distance of the year, the moon pulls away from the sun more slowly than usual. Look for Regulus, heart of Leo, in the west, 6 degrees to the left of the 15 percent crescent on July 2; and 8 degrees to the lower right of the 22 percent crescent on the next evening. It takes the moon eight full days after new to attain first quarter phase—on July 6, when it’s half full and 90 degrees from the sun. That evening, find Spica 9 degrees to the lower left of the D-shaped moon. Moving closer to Earth and speeding up, the moon takes only another 6.7 days to reach full. On July 7, Spica will appear 6 degrees to the lower right of the 62 percent gibbous moon. On Sunday, July 10, find Antares just 3 degrees to the lower right of the 90 percent moon.
On the evening of July 11, the 97 percent moon will appear very close to the galactic center—definitely not a good night to look for the Milky Way!
Super moon: The closest moon of 2022 occurs overnight on July 12-13. So, combined with the moon illusion—which makes our satellite seem larger at rising and setting—our satellite will seem largest at its rising in the east-southeast to southeast in daylight shortly before sunset on July 12, and at its setting in the southwest to west-southwest in twilight shortly before sunrise on July 13. Only marginally smaller, but visually more impressive, will be the full moon rising in east-southeast to southeast in twilight less than 40 minutes after sunset on July 13.
On July 14, the moon rises shortly before the end of evening twilight. On July 15, the 91 percent waning gibbous moon rises by 2 1/4 hours after sunset, within 7 degrees to the lower left of Saturn. On July 16, moonrise occurs 2 3/4 hours after sunset, allowing a short interval of dark skies for Milky Way viewing.
Attentive sky watchers will enjoy watching Saturn retrograde slowly past two stars in the tail of Capricornus, the Sea-goat. Look between late evening until first light of dawn, when it’s not too low in the sky. On the night of July 17-18, Saturn passes 1.4 degrees north of (above) third-magnitude Delta. On night of July 29-30, Saturn forms an isosceles triangle with Delta and fourth-magnitude Gamma, 1.6 degrees from each.
The moon returns to the evening sky late in month, but on its first day or two, you’ll need binoculars and an unobstructed view. On July 29, a half-hour after sunset, try for the 2 percent crescent, 6 degrees up in the west-northwest, with Mercury 3 degrees to its lower left. Fainter Regulus, 9 degrees to their upper left, will be a challenge. On July 30, 30 minutes after sunset, the 6 percent crescent moon is easier to see. Mercury shines through the twilight glow 12 degrees to the lower right of the moon. Faint Regulus is 5 degrees to the lower right of the moon and 7 degrees to the upper left of Mercury.
Morning sky: In July, morning twilight gets underway 1.7 to 1.6 hours before sunrise. So, for a dark sky good for viewing deep-sky objects, get out a bit before then, depending on how long you want to observe. The best dark mornings with little or no moonlight are July 1-10, and July 23-Aug. 9. For a good view of four naked-eye planets, get out between 1 and 1 1/2 hours before sunup, on any date in the month.
The stars we observe at first light of dawn on July mornings are in the same positions we’ll catch them at nightfall from mid-November to mid-December. Of bright objects, only the moon and planets will be in different positions. On July mornings, we note the Summer Triangle with its imbedded Cygnus Star Cloud in the western sky. The Milky Way runs nearly overhead, from Capella in the northeast, through Perseus, Cassiopeia, Cepheus, the Summer Triangle, and down to the Sagittarius Teapot, already about to set in the southwest as July begins. Soon, the Teapot and the galactic center will slip below the horizon.
On July 1 as twilight begins, Saturn is directly south, nearly halfway up from horizon to overhead, while brilliant Venus has just risen in east-northeast. On the line joining are two other planets, bright Jupiter and red Mars. The order of these four planets throughout this month from east to west remains Venus, Mars, Jupiter and Saturn. On July 1, they span an angle of 105 degrees.
Wait until one hour before sunrise, when Venus has climbed a little higher. Using binoculars, look for Aldebaran, eye of Taurus, the Bull, just 4 degrees south (to the lower right) of Venus. They appear closest this morning, as Venus moves eastward by 1.2 degrees per day. Also look for stars of the Hyades cluster, in the same binocular field. Nearly 14 degrees above Aldebaran lies an even more compact star cluster, the Pleiades or Seven Sisters, which resemble a miniature, short-handled dipper.
Wait a few minutes longer on July 1 and 2, and then look for Mercury in the brightening twilight, 13 degrees to the lower left of Venus. On July 1, the five planets from Mercury to Saturn span 118 degrees. But Mercury is moving sunward rapidly, passing behind the sun on July 16, so it will be visible for only a few more days.
To visualize how the planets will change in coming weeks, imagine the view from “above” the solar system, by an observer looking “down” from the constellation Draco in the northern sky. The revolutions of all the planets are counterclockwise around the sun. Inner planets move faster than the outer ones. Earth moves faster than Mars, Jupiter and Saturn, while Mercury and Venus move faster than Earth. On June 29, Earth was heading directly toward Jupiter. As we follow our curved orbit around the sun, which is below the eastern horizon in morning twilight, we will overtake Saturn on Aug. 14, Jupiter on Sept. 26, and Mars on Dec. 7. On those respective dates, as Earth passes between those planets and the sun, the planet will appear at opposition, in the western sky in morning twilight (and in the eastern sky in evening twilight), and will be visible all night.
So, as we observe the morning sky in coming months, we will see the three outer planets progress toward the western horizon.
Mercury and Venus, already ahead of us, are pulling even farther ahead. Mercury will pass superior conjunction, on the far side of the sun, on July 16. Venus will do so on Oct. 22.
After opposition of an outer planet, or superior conjunction of an inner planet, we’ll find the planet in the evening sky.
Beginning with the full moon of July 13, we’ll see a lineup of the moon and four planets in the morning sky. One hour before sunrise is a good time to look. Watch the waning moon pass the four planets in turn.
On July 15, see the 95 percent moon within 9 degrees to the lower right of Saturn. On the next morning, the 89 percent moon will be 9 degrees to the upper left of Saturn.
On July 18, the 72 percent gibbous moon appears 9 degrees to the lower right of Jupiter. The next morning, the 62 percent moon will be 5 to 6 degrees to the lower left of Jupiter. On July 20, the moon will be at last quarter phase, 90 degrees west of the sun, appearing as a reverse “D” and half full.
On July 21, the 41 percent fat crescent moon appears within 2 degrees to the upper right of Mars. The next morning, the 32 percent crescent moon will appear 10 degrees to the lower left of Mars, and within 10 degrees to the upper right of the Pleiades star cluster. On July 23, the 23 percent crescent moon appears 5 degrees below the Pleiades and 9 degrees above Aldebaran. Wonderful views for binoculars!
On July 24, find the 16 percent lunar crescent 9 degrees to the left of Aldebaran, and 22 degrees to the upper right of Venus. On the next morning, the 9 percent crescent closes to within 12 degrees to the upper right of Venus. On July 26, the slender 5 percent crescent moon is low in the east-northeast, with Venus within 4 degrees to its lower right. In east to east-southeast, watch for Orion coming up sideways, with bright stars reddish Betelgeuse and bluish Rigel, and a vertical three-star belt between them. Using binoculars, look 15 degrees lower left of Venus for Gemini’s “twin” stars, Pollux and Castor, 4.5 degrees apart.
On July 27, about 50 minutes before sunrise, try for the old, 2 percent moon, 30 degrees north of east and 3 degrees up. Using binoculars, try for Pollux 3 degrees to the left of the moon, and Castor 4.5 degrees to the upper left of Pollux and 6 degrees to the upper left of the moon.
On July 28, the moon is new at 10:55 a.m.
The South Delta Aquariid meteor shower reaches peak in the predawn hours of July 30. The radiant is highest in the south, about 13 degrees above the first-magnitude star Fomalhaut and left of Saturn, around three hours before sunrise. The popular Perseid meteor shower two weeks later will be spoiled by full moonlight this year.
On the morning of Sunday, July 31, four bright planets span 143 degrees, from Venus to Saturn.
Faint planets: On mornings of Aug. 1 and 2, before start of twilight, Uranus, of magnitude 5.8 in Aries—east of a compact isosceles triangle of similarly bright stars Omicron, Sigma and Pi—is easy to spot through binoculars, within 1.4 degrees north of Mars.
Neptune in July is of magnitude 7.9 to 7.8, near the Aquarius-Pisces border, 12.1 to 13.5 degrees west-southwest of Jupiter. Neptune began retrograde on June 28, so it creeps very slowly west-southwest in July.
Sky Calendar includes illustrations of many of the events described in this article. To subscribe or to view a sample issue, visit www.abramsplanetarium.org/skycalendar.
Robert Victor originated the Abrams Planetarium monthly Sky Calendar in October 1968, and still produces issues occasionally. He enjoys being outdoors sharing the wonders of the night sky. Robert Miller, who provided the twilight charts, did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.