Skywatch Line for Friday, June 3, through Sunday, June 5, 2016

This is Dudley Observatory’s Skywatch Line for Friday, June 3, through Sunday, June 5, written by Sam Salem.

The Sun rises at 5:19am and sets at 8:29pm on Friday. The New Moon occurs on Saturday at 11:00pm. The Moon rises and sets close to the sunrise and sunset time on the day of New Moon. The New Moon can’t be seen in the sky. Its lighted hemisphere is facing away from us and it is too close to the Sun’s glare to be visible. The only time we can see the New Moon from Earth is during a solar eclipse when the Moon passes in front of the Sun and the night side of the Moon can be seen in silhouette against the disk of the Sun. In most months, the Moon passes above or below the Sun as seen from Earth. If the Moon always passed directly between the Sun and Earth at New Moon, a solar eclipse would take place every month. On Sunday, the Moon rises at 6:04am and sets at 9:01pm. Try to spot the slim waxing crescent in the west shortly after sunset.

Mars, Jupiter and Saturn can be observed in the evening sky all month long. Mars and Saturn sit very low the southeast sky at nightfall. You might have to wait an hour or so after darkness falls before seeing these two planets shining together. Mars was closest to Earth in a decade on May 30 and Saturn will be at its closest this Friday. Mars and Saturn travel westward across the night sky from dusk until dawn. The Mars-Saturn-Antares triangle stands highest in the south after midnight when the planets are likely to be sharpest in a telescope. Look lower left of Mars for Saturn and lower right for orange Antares.

On spring and summer evenings, the northern sky’s most recognized asterism, the Big Dipper, shines highest in the sky. Look at the naked-eye double star Mizar and its fainter companion star Alcor in the handle of the Big Dipper. Spot Mizar first, as the middle star of the Big Dipper’s handle. Look closely, and you’ll see Alcor right next to Mizar. Mizar and Alcor appear so closely linked in that they’re often said to be a test of eyesight. Mizar itself became known a double star in 1650. It was the first double star to be seen through a telescope. In 1889, a spectroscope revealed that Mizar’s brighter telescopic component consisted of two stars, making Mizar the first binary star ever discovered by spectroscopic means. At a later date, Mizar’s dimmer telescopic component also showed itself to be a spectroscopic binary, meaning that Mizar consists of two sets of binaries, making it a quadruple star. As for Alcor, In 2009, two groups of astronomers independently reported that Alcor actually is itself a binary, consisting of Alcor A and Alcor B. Astronomers now believe that the Alcor binary system is gravitationally bound to the Mizar quadruple system. Making six stars in all, where we see only two with naked eye.

The Albany Area Amateur Astronomers will hold a Star Party at Landis Arboretum on Friday and Saturday at 9:30pm, weather permitting. Club members will provide views of nebulae, star clusters, galaxies, double stars, planets and other interesting celestial objects. Check the link below for directions.

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