![]() ![]() The line is about fist and a half long, from lower right to upper left. Fainter Mercury, even fainter Regulus, and puny Mars form a straight diagonal line a little way above Venus. Look for Venus about three fists at arm's length to its lower right. Spot the crescent Moon in the west-southwest about 30 minutes after sunset. ■ In late twilight, look about a fist at arm's length above the Moon for Denebola, Beta Leonis. The top of the kite is bent slightly down, as if something hit it. The Kite, rather narrow, extends upper right from Arcturus by 23°, about two fists at arm's length. Its pale ginger-ale tint always helps identify it.Īrcturus forms the bottom point of the Kite of Boötes. ■ As summer progresses, bright Arcturus moves down the western side of the evening sky. They used to be rare, but they're becoming more common as Earth's atmosphere changes, probably due to the extra methane at very high altitudes as a result of global warming. Noctilucent cloud season runs from mid-May to mid-August (in the Northern Hemisphere). Would you recognize pearly, night-glowing noctilucent clouds if you saw them? They're the most astronomical of all cloud types, with their extreme altitude and formation on, among other things, meteoric dust particles. ■ At the end of these long summer twilights, look low in the northwest and north. ■ Now the crescent Moon is easier to spot low in the west early twilight, helping mark the way to three planets as shown above. Low in bright twilight, the waxing crescent Moon passes over Mercury, Venus, and fainter Regulus and Mars. ■ About 20 minutes after sunset, start looking very low in the west-northwest for Venus, lesser Mercury, and the thin crescent Moon as shown below. The Teapot will tilt farther and farther for the rest of the summer - or for much of the night if you stay out late. ■ With the advance of summer the Sagittarius Teapot, in the south-southeast after dark now, is starting to tilt and pour from its spout to the right. If you have very sharp eyes, can you resolve the Mu pair without using binoculars? They're oriented almost exactly the same way as Lambda and Upsilon. The fainter one is indeed the nearer one.īetween the Cat's Eyes and the Teapot's spout are the open star clusters M6 and especially M7, showy in binoculars.Ī line through the Cat's Eyes points west (right) by nearly a fist-width toward Mu Scorpii, a much tighter pair known as the Little Cat's Eyes. Both are blue-white giants, 500 and 700 light years away, respectively. And the cat has a bleary eye Upsilon is fainter than Lambda (they're magnitudes 2.6 and 1.6). They're 0.6° apart and canted at an angle the cat is tilting its head to the right. These are Lambda and fainter Upsilon Scorpii, known as the Cat's Eyes. Look for the two stars especially close together in Scorpius's tail. How low depends on how far north or south you live: the farther south, the higher. ■ The tail of Scorpius is low due south after dark, to the lower right of the Sagittarius Teapot. See page 54 of the July Sky & Telescope, which includes lots of telescopic sights around it. It's 4° above (northwest of) Sagitta's tail and currently poses upside down. For more on Sagitta and its telescopic cluster M71, see the July Sky & Telescope, page 43.Īlso in the vicinity is the lovely little binocular asterism The Coathanger. The Arrow points lower left past the Dolphin's nose. Look for it closer to Altair's upper left. Sagitta, the Arrow, is smaller and fainter. He's leaping leftward just below the summer Milky Way. Little Delphinus is about a fist at arm's length lower left of Altair. ■ Now that Altair is getting nice and high in the east-southeast, and with the evenings moonless, it's time to greet the Dolphin and the Arrow. That may be why this image (which has a resolution of only a few pixels) appears mottled. The faster a star spins the stronger its magnetic activity will be, including starspots. The disk of Altair, imaged by the CHARA interferometric array on Mt. It spins so fast that, using interferometry, astronomers were able in 1999 to confirm that it is widened around its equator into a very ellipsoid shape. The third star of the Summer Triangle is Deneb, less bright, left of them.Ībove Altair by a finger-width at arm's length is little Tarazed, 3rd magnitude and orange, which helps to identify it.Īltair is a fast-spinning, white type- A star, somewhat larger and hotter than the Sun, only 17 light-years away. ![]() It's the second-brightest star on the eastern side of the sky, after Vega higher to its upper left. ■ Altair shines high in the east-southeast after dark.
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