Special to CosmicTribune.com, July 28, 2025

Excerpts from weekly Sky&Telescope report.

SUNDAY, JULY 27

■ Use the low crescent Moon to guide you to Mars and Denebola in the fading twilight this evening, as shown below.

At dusk across four days, the waxing crescent Moon moves from lower right of Mars to much closer lower right of Spica.

MONDAY JULY 28

■ At this time of year the Big Dipper hangs diagonally in the northwest after dark. From the Big Dipper’s midpoint, look three fists to the right to find Polaris, not very bright at 2nd magnitude.

Polaris is the end of the Little Dipper’s handle. The only other Little Dipper stars that are even moderately bright are the two forming the outer end of its bowl: Kochab and Pherkad. These evenings you’ll find them to Polaris’s upper left by about a fist and a half at arm’s length, as shown above. They’re called the Guardians of the Pole, since they ceaselessly circle around Polaris through the night and through the year.

They are giant orange-hot and white-hot balls of gas, respectively, spectral types K4 III and A2 III, located 131 and 490 light-years away.

TUESDAY, JULY 29

■ One of the brightest Cepheid variable stars in the sky — a naked-eye, glance-up-to-check-it star waiting there for you — is . . . Eta Aquilae.

Never heard of it? It’s located 8° due south of Altair and pulses from magnitude 4.3 to 3.4 and back every 7.18 days. That’s slightly more than a doubling in brightness. Its rise to maximum is faster than its fade to minimum, as with other classical Cepheids. Its period is so close to a week that you’ll find it repeating itself on the same weekdays for a month or two at a time.

Judge its brightness by comparing it between Theta Aquilae, magnitude 3.2; Delta Aql, mag. 3.4; Beta Aql; mag. 3.7; and Iota Aql, mag. 4.4. They’re all part of Aquila’s flying-eagle stick figure.

WEDNESDAY, JULY 30

■ The Moon, a fat crescent just 1½ days short of first quarter, hangs 2° below Spica this evening, about a finger’s width at arm’s length.

THURSDAY, JULY 31

■ Summer advances. Bright Vega passes its closest to overhead around 11 p.m. now, depending on how far east or west you are in your time zone.

Deneb crosses closest to the zenith almost exactly two hours after Vega. But to see Deneb straight up you need to be farther north, close to latitude 45°: Portland, Minneapolis, Montreal, central Maine, southern France, northern Italy, Odesa, Kherson. Mariupol.

FRIDAY, AUGUST 1

■ First-quarter Moon; exactly so at 8:41 a.m. EDT. At dusk, a half a day later, look for the Moon’s terminator to already be very slightly convex.

Venus and Jupiter draw closer together in the dawn. At 9° separation now they’re already pretty spectacular . . . if you look early before dawn gets too bright!

SATURDAY, AUGUST 2

■ Titan casts its shadow on Saturn tonight. Every 15 years Titan, Saturn’s largest moon, repeatedly crosses Saturn’s face from Earth’s viewpoint — and, more visibly, cast its very tiny black shadow onto Saturn’ face. A new series of these events is under way. They will continue every 16 days until October.

Tonight Titan’s shadow crosses Saturn from 6:25 to 11:04 UT August 3rd (UT date). That’s from 2:25 a.m. to 7:04 a.m. August 3rd Eastern Daylight Time; 11:25 p.m. to 4:04 a.m. PDT. Wherever you are, Saturn rises by 11 p.m. local daylight-saving time and is high in good seeing before dawn begins. So all of North America now gets a chance.

SUNDAY, AUGUST 3

■ This evening the waxing gibbous Moon hangs hardly more than 1° below orange Antares, the 1st-magnitude heart of Scorpius. “The neutral gray of the lunar surface always seems to enhance the color of whatever star or planet the Moon is near,” writes Gary Seronik in the August Sky & Telescope. Do you think so too?