Sunday, July 7 You should be able to glimpse Jupiter in the predawn sky this week. The giant planet lies 4° high in the east-northeast 30 minutes before sunrise this morning. It shines at magnitude –1.9, nearly 25 times brighter than its neighbor to the upper right, Mars. Both planets will grow more conspicuous in the coming weeks as they climb higher in the predawn sky. As twilight starts to fade, Saturn will become prominent in the southwestern July sky. // Efrain Morales Rivera Monday, July 8 Saturn currently shines at magnitude 0.5 in eastern Virgo, where it sits just 0.5° (the width of a Full Moon) due south of 4th-magnitude Kappa (κ) Virginis. The planet appears stationary relative to the background stars tonight and barely budges the rest of the week. Saturn stands approximately 30° high in the southwest around 10 p.m. local daylight time and doesn’t set until after midnight. Although the planet looks attractive with naked eyes, it truly dazzles when you view it through a telescope. Even a small instrument reveals the distant world’s 18"-diameter disk and the spectacular rings, which span 40" and tilt 17° to our line of sight. New Moon occurs at 3:14 a.m. EDT. At its new phase, the Moon crosses the sky with the Sun and so remains hidden in our star’s glare. Tuesday, July 9 Mercury reaches inferior conjunction, passing between the Sun and Earth, at 3 p.m. EDT. The innermost planet will return to view before dawn in about two weeks. Wednesday, July 10 The waxing crescent Moon passes near Venus in tonight’s twilight sky. The brilliant planet appears 7° north (to the upper right) of our satellite as darkness falls. You shouldn’t have any problem spotting Venus, which shines at magnitude –3.9 and appears about 10° above the horizon 30 minutes after sunset. If you turn a telescope on the planet, you’ll see a disk that spans 11" and appears nearly full. Thursday, July 11 Comet PANSTARRS (C/2011 L4) should glow around 10th magnitude this week, so you’ll need a telescope to follow its trek back into the solar system’s depths. Fortunately, it remains on view all night for observers in the Northern Hemisphere. Your best guide to this dirty snowball is the 4th-magnitude star Thuban (Alpha [α] Draconis). This evening, the comet appears some 4° southeast of the star. (PANSTARRS moves about 1° farther south with each passing night.) Thuban’s main claim to fame is that it served as the Pole Star between 4,000 and 5,000 years ago, when the ancient Egyptians built their largest pyramids. Rhea, Dione, and Tethys point the way to Enceladus and Mimas the night of July 12/13. // Astronomy: Roen Kelly Friday, July 12 Saturn has 62 known moons, a handful of which show up through modest amateur telescopes. Any instrument reveals 8th-magnitude Titan, and a 4-inch scope also brings in Tethys, Dione, and Rhea. This evening provides a nice opportunity to spy two fainter moons through 10-inch or larger instruments. Both Mimas and Enceladus lie near greatest western elongation tonight and will show up under good conditions not far off the rings’ western edge. Use the outer, brighter moons Rhea and Dione as guides to these elusive inner satellites. From Astronomy - The Sky this Week
Posted on: Sun, 07 Jul 2013 09:07:08 +0000
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