This Week’s Sky at a Glance, August 29 – September 6 By: Alan MacRobert | August 29, 2014 As the stars come out this week, the first one you see may be Arcturus shining high in the west. As the sky gets a little darker, look to its right for the Big Dipper scooping down in the northwest. The Great Square of Pegasus is well up in the east as soon as nightfall is complete. Its larger than your fist at arms length and currently stands on one corner. Seen from your latitude at your time, how close is its balance to being perfect? The moon, and other highlights: Friday, August 29: The Moon is coming back into the evening sky. Look for the waxing crescent low in the west-southwest in twilight, as shown below. Can you make out Spica twinkling beneath it? Binoculars help. Far to their upper left are Saturn and Mars. Saturday, August 30: The waxing crescent Moon now shines closer to Saturn and Mars, as shown above. Can you see little Alpha Librae [Zubenelgenubi] in the middle of the narrow triangle they make? Monday, September 1: First-quarter Moon this evening and Tuesday evening (exactly first quarter at 7:11 a.m. Eastern Daylight Time Tuesday morning). Its passing over Scorpius, as shown below. Wednesday, September 3: Look lower left of the Moon right after nightfall for the Teapot of Sagittarius, tilting and pouring to the right. Thursday, September 4: In Fridays dawn, use binoculars to help pick up Venus just above the eastern horizon about 30 minutes before sunrise. Its far to the lower left of Jupiter. Can you make out Regulus [the brightest star in Leo the Lion], less than a hundredth as bright, within 1° of Venus? Friday, September 5: Saturn, Mars, Delta (δ) Scorpii, and Antares form an equally-spaced ragged line in the southwest at dusk, as shown below. Delta Scorpii [Dschubba] used to be a bit dimmer than Beta [Graffias]above it. Then in July 2000 it doubled in brightness. It has remained bright, with fluctuations, ever since. [A similar thing happened in the 1930s with Gamma Casiopeiae, the middle star in the W, or M, depending on how youre looking at it.] Look high above the Moon this evening for Altair [the brightest star in Aquila the Eagle]. Saturday, September 6: This evening look to the right of the Moon, by a little more than a fist-width at arms length, for two faintish (3rd-magnitude) stars: Alpha and Beta Capricorni, one above the other. Alpha is the one on top. With sharp vision, you can barely see that its double. Binoculars resolve it easily. This Weeks Planet Roundup, from Dusk to Dawn: Mercury (about magnitude –0.2) remains quite deep in the sunset, as it always does during its evening apparitions that happen in late summer and early fall. Scan for Mercury with binoculars just above the horizon due west about 20 minutes after sundown. Mars and Saturn, both magnitude +0.6, glow in the southwest at dusk, moving apart after their conjunction last week. Theyre 4° apart on August 29th and 7° by September 5th. Mars is the one on the lower left early in the week, directly left later. Off to their left are fainter Delta Scorpii [Dschubba], then Antares. Compare all their colors. Venus (magnitude –3.9) and Jupiter (magnitude –1.8) shine in the east-northeast during dawn. Jupiter is the higher and easier one to spot. Watch far to its lower left for Venus rising as dawn grows bright. The two planets continue drawing farther apart: from 12° apart on August 30th to 20° by September 5th. Jupiter is moving higher, and Venus is gradually sinking lower.
Posted on: Fri, 29 Aug 2014 16:06:27 +0000
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