Special to CosmicTribune.com, September 9, 2024

Excerpts from weekly Sky&Telescope report.

SUNDAY, SEPTEMBER 8

■ Right after nightfall, the thickening crescent Moon shines low in the southwest. Look almost two fists upper left of it for orange Antares.

Two thirds of the way from the Moon to Antares is the near-vertical row of three stars marking the head of Scorpius. The brightest of the three is the middle one, Delta Sco, not all that much fainter than Antares.

■ On Monday morning the 9th, Mercury and Regulus will be in conjunction, 0.5° apart. Look low in the east-southeast by east, and bring binoculars. Regulus will be to Mercury’s right. Mercury is currently 9 light-minutes from us; Regulus is 78 light-years away.

MONDAY, SEPTEMBER 9

■ The Moon, nearly first quarter, is very close to 3rd-magnitude Pi Scorpii early this evening, as suggested below. Binoculars will help; so will covering the Moon with your fingertip.

The Moon’s dark limb will occult (cover) Pi Scorpii in reasonably dark twilight for parts of easternmost Canada and the northeastern U.S.

The waxing Moon steps eastward across Scorpius and Sagittarius day be day, as the constellations edge westward and down for the season about 15 times more slowly.

Remember, the Moon is drawn here three times its actual apparent size, and it’s positioned for an observer at 40° north latitude, 90° west longitude. So don’t expect its position with respect to Pi Scorpii to look just like this on the 9th, occultation or no.

■ 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.

■ Alphecca is your guide star for checking whether the naked-eye recurrent nova T Coronae Borealis has exploded! That much-awaited event could happen any month now… or not. At peak brightness, T Cor Bor may nearly match Alphecca for a day or two. With binoculars or a small telescope, you might be among the very first catch it on the rise.

Will the Northern Crown add a new gem this year or not? T Coronae Borealis is normally 10th magnitude. The dot marks the spot to watch. I’ve gotten awfully familiar with that blank spot in my 10×50 binoculars. Alphecca, Corona’s brightest star, is 5.7° to the celestial west of it. Bob King photo.

TUESDAY, SEPTEMBER 10

■ First-quarter Moon (exactly first-quarter at 2:06 a.m. EDT tonight, after the Moon has set for most of us.)

As soon as the stars come out this evening, look for orange Antares about 6° to the Moon’s right. Somewhat farther on in that same direction is Delta Scorpii.

WEDNESDAY, SEPTEMBER 11

■ Just left of the Moon this evening is the spout of the Sagittarius Teapot, as shown up above (during evening in North America).

■ You can see in the stars that the season is changing; we’ve reached the time of year when, just after nightfall, Cassiopeia has already climbed a little higher in the northeast than the Big Dipper has sunk in the northwest.

Cas marks the high northern sky in early evening during the chilly fall-winter half of the year. The Big Dipper takes over for the milder evenings of spring and summer.

Almost midway between them stands Polaris, due north. It’s currently a little above the midpoint between the two.

THURSDAY, SEPTEMBER 12

■ This evening the Moon shines in the Teapot’s handle. Cover the glary Moon with your fingertip to help reveal the stars around it.

FRIDAY, SEPTEMBER 13

■ Bright Vega now passes the zenith an hour after sunset during late twilight, for those of us at mid-northern latitudes. Vega is bigger, hotter, and 50 times brighter than our Sun. But at a distance of 25 light-years, it’s 1,600,000 times farther away.

■ Saturn is the bright little dot in the southeast after dark, lower right of the Great Square of Pegasus. A telescope tonight will show Saturn’s biggest and brightest moon, 8th-magnitude Titan, glimmering at its maximum elongation about four ring-lengths to Saturn’s east. A 3-inch telescope can pick it up. A 4-inch will begin to show its orange color, caused by its smoggy atmosphere.

Regulus gets easier now that it’s higher in the dawn. By Saturday morning the 14th, it’s a good 8° above Mercury.

SATURDAY, SEPTEMBER 14

■ As dusk turns to night, Arcturus twinkles due west. It’s getting lower every week. From Arcturus, the narrow, kite-shaped pattern of Boötes extends a little more than two fists at arm’s length to the upper right.

Off to the right in the northwest, the Big Dipper is now turning more and more level.

SUNDAY, SEPTEMBER 15

■ The waxing gibbous Moon forms a nearly equilateral triangle with Saturn to its left and Fomalhaut to its lower left. The triangle is about 20° on a side.

  Sept. 8-15: Moon occults Pi Scorpii, Sept. 9, The Sky