Special to CosmicTribune.com, July 22, 2024

Excerpts from weekly Sky&Telescope report.

SUNDAY, JULY 21

■ This evening you’ll find that the low Moon forms a huge, nearly vertical line with Altair about three fists above it and Vega the same distance above Altair, near the zenith.

■ Look a finger-width at arm’s length above Altair for its eternal little sidekick Tarazed (Gamma Aquilae), a modest magnitude 2.7 compared to Altair’s showy 0.7. But looks are deceiving. Altair appears so bright because it’s one of our near stellar neighbors, just 17 light-years away. Tarazed is an orange giant star about 380 light-years farther in the background. It’s 170 times as luminous as Altair!

MONDAY, JULY 22

■ Starry Scorpius is sometimes called “the Orion of Summer” — for its brightness, its blue-white giant stars, and its prominent red supergiant (Antares in the case of Scorpius, Betelgeuse for Orion). But Scorpius passes a lot lower across the southern sky than Orion does, for those of us at mid-northern latitudes. That means it has only one really good evening month: July.

Catch Scorpius due south just after dark now, before it starts to tilt lower toward the southwest.

TUESDAY, JULY 23

■ We’re only a third of the way through summer (astronomical summer, that is), but already Cassiopeia is getting well up after dark. Look for its tilted W pattern in the north-northeast.

High above it is dimmer Cepheus, weak in the moonlight. Below it, the head of Perseus is on the rise. The farther north you live the higher they will all appear.

WEDNESDAY, JULY 24

■ 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. And they’re fairly rare — though becoming more common in recent years as the atmosphere changes.

■ Late this evening the waning gibbous Moon rises with yellowish Saturn glowing a few degrees to its right. Although they may look like a pair, Saturn is 3,500 times farther away.

THURSDAY, JULY 25

■ Fourth star of the Summer Triangle? The next-brightest star near the Summer Triangle, if you want to turn it into a quadrilateral, is Rasalhague (Alpha Ophiuchi), the head of Ophiuchus. Look high toward southeast after dark, and the scene will be like this:

Face southeast after dark in July, look high, and there’s the big, Milky-Way-crossed Summer Triangle. Add Rasalhague to its right, and you’ve got a pretty good cut diamond standing on its point. Bob King photo

FRIDAY, JULY 26

■ Week by week, Venus is edging up in the west through the afterglow of sunset. Fading Mercury soon drops down. And can you make out fainter, twinkly Regulus near Mercury? See below.

Look very low in the west as twilight fades for the two inner planets, with Regulus keeping them company. Binoculars will help; the objects’ visibility in twilight is exaggerated here,

SATURDAY, JULY 27

■ With the advance of summer the Sagittarius Teapot, sitting in the south left of Scorpius, is tilting to pour from its spout to the right. As it moves westward, the Teapot will tilt farther and farther for the rest of the summer and into early fall — or far into the night if you stay out late.

SUNDAY, JULY 28

■ The tail of Scorpius is at its best low due south right after night is fully dark. Find it lower right of the Teapot’s spout by a fist at arm’s length or less. Or about a fist and a half lower left of Antares. How low it will appear depends on how far north or south you live: the farther south, the higher.

Spot the two stars especially close together in the tail. These are Lambda and fainter Upsilon Scorpii, known as the Cat’s Eyes. They’re canted at an angle; the cat has a bleary eye and is tilting his head to the right. Lambda is brighter than Upsilon; they’re magnitudes 1.6 and 2.6. Both are blue-white supergiants, 700 and 500 light years away, respectively. Yes, the nearer one is fainter.

Between the Cat’s Eyes and the Teapot’s spout are the open star clusters M6 and especially M7, showy in binoculars.