Special to CosmicTribune.com, June 30, 2025

Excerpts from weekly Sky&Telescope report.

MONDAY, JUNE 30

■ After nightfall, look due south for orange Antares nearly on the meridian. Around and upper right of Antares are the other, whiter stars forming the distinctive pattern of upper Scorpius. The rest of the Scorpion runs down from Antares toward the horizon, then left.

Three doubles at the top of Scorpius. The head of Scorpius — the near-vertical row of three stars upper right of Antares — stands nearly vertical. The top star of the row is Beta Scorpii or Graffias: a fine double star for telescopes, separation 13 arcseconds, magnitudes 2.8 and 5.0.

Near Antares, three nice double stars and the globular cluster M4 await small-telescope users.

Akira Fujii took the photo below before Delta Scorpii entered its historic brightening.

Just 1° below it is the very wide naked-eye pair Omega¹ and Omega² Scorpii. They’re 4th magnitude and ¼° apart. Binoculars show their slight color difference; they’re spectral types B9 and G2.

Upper left of Beta by 1.6° is Nu Scorpii, separation 41 arcseconds, magnitudes 3.8 and 6.5. In fact it’s a telescopic triple. High power in good seeing reveals Nu’s brighter component itself to be a close binary, separation 2 arcseconds, magnitudes 4.0 and 5.3, aligned almost north-south.

TUESDAY, JULY 1

■ 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 tiny black shadow onto Saturn’ globe. A new series of these events is under way. They will continue every 16 days until October.

Tonight Titan’s shadow crosses Saturn from 7:40 to 13:03 UT July 2nd (UT date). That’s from 3:40 a.m. to 9:03 a.m. Eastern Daylight Time July 2nd; 12:40 a.m. to 6:03 a.m. PDT. Remember, Saturn only rises around midnight or 1 a.m. local time and doesn’t get high into good seeing until just before the beginning of dawn. Nearly all of North America now gets a chance.

WEDNESDAY, JULY 2

■ First-quarter Moon (exact at 3:30 p.m. EDT). After sunset the Moon hangs between Spica to its left and Gamma Virginis, a telescopic double star, to its upper right.

THURSDAY, JULY 3

■ More Scorpius: To the right of Antares is that roughly vertical row of Beta, Delta, and fainter Pi Scorpii. The middle one, Delta Sco, is the brightest — obviously so. But it didn’t used to be. It used to be like Beta.

Delta is a strange variable star, a fast-rotating blue subgiant throwing off luminous gas from its equator. Assumed for centuries to be stable, Delta doubled in brightness unexpectedly in summer 2000, then dipped down and up again several times from 2005 to 2010, and has remained essentially steady at peak brightness (magnitude 1.7) ever since.

Delta has a smaller orbiting companion star that was suspected to trigger activity at 10.5-year intervals. Astronomers watched to see whether the system would have another flareup around 2022, when the companion star made its third pass by the primary star since 2000. But nothing happened. No one knows what might happen next, or when.

FRIDAY, JULY 4

■ If you have a dark enough sky, the Milky Way now forms a magnificent arch high across the whole eastern sky after nightfall is complete. It 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.

Mars and Regulus continue drawing apart as they sink low in the western twilight this week. A line from Mars through Regulus points down to fading Mercury. Bid them goodbye for the season while you still can.

SATURDAY, JULY 5

■ The Big Dipper, high in the northwest after dark, is beginning to turn around to “scoop up water” through the evenings of summer and early fall.

■ Look low in the northwest or north at the end of these long summer twilights. Would you recognize noctilucent clouds if you saw them there? They’re the most astronomical of all cloud types, what with their extreme altitude and, sometimes, their formation on meteoric dust particles. They used to be rare, but they’ve become more common in recent years as Earth’s atmosphere changes. See Bob King’s Nights of Noctilucent Clouds.

SUNDAY, JULY 6

■ This evening the waxing gibbous Moon shines in the head of Scorpius, with Delta Scorpii above it and Antares to its left. And tonight the Moon’s dark limb occults Pi Scorpii, magnitude 2.9, for observers nearly all across North and Central America.

  3 double stars and M4, June 30-July 6: Near Antares, the cluster, The Sky