Special to CosmicTribune.com, September 15, 2025

Excerpts from weekly Sky&Telescope report.

SUNDAY, SEPTEMBER 14

■ Altair is the bright star high towards the south in early evening. Find little Sagitta, the Arrow, barely a fist at arm’s length above it.

Now imagine rotating the Arrow on its point a third of a turn counterclockwise. Its middle star would now rest almost at M27, the Dumbbell Nebula. With a total magnitude of 7½, the Dumbbell is a big but subtle gray glow nearly 0.1° wide, easily seen in binoculars or a finderscope under a dark sky. In a 4- to 8-inch telescope it’s a rectangle or hourglass. It’s the brightest planetary nebula in the sky if you sum up all of its spread-out light.

 The Dumbbell Nebula, M27. This view is 0.9° wide, about the size of a 60-power field of view in an ordinary telescope eyepiece. North is up, east is left. The star 14 Vulpeculae is magnitude 5.6. The star HD 189733, magnitude 7.7, is a yellow-orange K dwarf 63 light-years away from us, notable for having a hot-Jupiter exoplanet closely orbiting it. The nebula is very far in its background, about 1,360 light-years away.

■ Back to Altair. Now that you’ve found Sagitta, here’s another, easier little neighbor of Altair. Look about a fist to the star’s left soon after dark, or to its upper left as the evening grows late. There’s Delphinus, the Dolphin, a little bigger and brighter than Sagitta. Thye Dolphin’s stick-figure pattern leaps in the direction away from Altair. Again, binoculars help.

MONDAY, SEPTEMBER 15

■ The two brightest stars of September evenings are Vega high overhead and Arcturus in the west, both magnitude 0.

Draw a line from Vega down to Arcturus. A third of the way down you cross the dim Keystone of Hercules. Two thirds of the way you cross the dim semicircle of Corona Borealis with its one modestly bright star: Alphecca, the gem of the crown.

Just off the Corona semicircle, the recurrent nova T Coronae Borealis still has not erupted (see where to check). This is looking like one more example of astronomy popularizers’ notorious eagerness to overpredict exciting but chancy things to the public. T Cor Bor will blow up. . . one of these years. . . eventually. My personal hunch, considering Bayesian priors as best I can? 50-50 chance by 2028.

■ The waning Moon bunches up with Jupiter, Pollux, and Castor in the early-morning hours of Tuesday. They rise around midnight and shine high in the east by the beginning of dawn.

By that time Venus, and Regulus 4° under it, are in view way down below.

TUESDAY, SEPTEMBER 16

■ Vega now passes the zenith about 50 minutes after sunset, for those of us at mid-northern latitudes. How early can you pick it up through the twilight? It soon becomes more obvious.

Vega is bigger, hotter, and 50 times brighter than our Sun. But at a distance of 25 light-years, it’s 1.6 million times farther away.

WEDNESDAY, SEPTEMBER 17

■ “Late summer and early fall are among the most enjoyable seasons for stargazing,” writes Matthew Wedel in the September Sky & Telescope. “Nights are getting longer, temperatures are usually not too bad, and there’s a lot up there to choose from. … One of my favorites [is the] globular cluster M2 in Aquarius.” At magnitude 6.6 it’s visible in a good finderscope under a decent sky. It’s easy to locate west of Alpha Aquarii and north of Beta Aquarii if you memorize the shape of the triangle it makes with those two 3rd-magnitude stars.

Just don’t be jealous of the Hubble view.

■ At dawn Thursday morning, the crescent Moon hangs above Venus as shown below. Take a look to get ready for Friday morning!

THURSDAY, SEPTEMBER 18

■ Set your alarm: A strikingly close Moon-Venus conjunction awaits you in the ease during early dawn, Friday morning with fainter Regulus thrown in as an extra. As shown below.

This presents a nice photo opportunity. Find a good view low to the east, frame the Moon and its companions with nice foreground, and brace your phone or camera on something motionless. Start early! Try zooming in by different amounts.

The Moon actually occults Venus for northernmost Canada, Greenland, Iceland, all Europe, northwestern Africa, and northwestern Asia. Map and timetables.

 Venus and the thin crescent Moon shine less than a Moon-diameter apart on Friday morning as seen from much of North America. . . while Venus is also having its conjunction with Regulus about ½° from it. Regulus, magnitude 1.4, is only about 1% as bright as Venus, magnitude –3.9.

FRIDAY, SEPTEMBER 19

■ Titan, Saturn’s largest moon, casts its shadow onto Saturn’s face tonight in the second-to-last of these events for another 15 years. Around when we see Saturn’s rings nearly edge on, Titan repeatedly crosses in front of Saturn from Earth’s viewpoint — and, more visibly, casts its tiny black shadow onto the planet.

Tonight, Titan’s shadow skims just inside Saturn’s northern limb from 5:09 to 7:34 UT September 20th (UT date). In EDT that’s tonight from 1:09 a.m. to 3:34 a.m. In PDT it’s tonight from 10:09 p.m. to 12:34 a.m.

Saturn is up all night now, though it is highest in the steadiest seeing around the middle of the night local time. So all of North and Central America again get a good chance at this event.

SATURDAY, SEPTEMBER 20

■ Arcturus shines in the west these evenings as twilight fades out. Capella, equally bright, is barely rising in the north-northeast (depending on your latitude; the farther north you are the higher it will be.) They’re both magnitude 0.

Later in the evening, Arcturus and Capella shine at the same height in their respective compass directions. When will this happen? That depends on both your latitude and longitude.

SUNDAY, SEPTEMBER 21

■ By 9 or 10 p.m. two of the best-known deep-sky objects, the Double Cluster in Perseus and the Great Andromeda Galaxy M31, are in high view in the east. They’re only 22° (two fists) apart. They’re both cataloged as 4th magnitude but to the naked eye they look rather different from each other, the more so the darker your sky. They’re below Cassiopeia and farther to Cassiopeia’s right, respectively. Sky too bright? Use binoculars!

The two clusters of the Double Cluster (NGC 869 and NGC 884) are at very similar distances about 7,600 light-years away. M31, at 2.5 million light-years, is 330 times farther.

■ New Moon (at 3:54 p.m. EDT).

  high in the East, M31, Sept. 14-21: Andromeda galaxy, The Sky