Skywatch Line for Friday, March 17, through Sunday, March 19, 2017

This is Dudley Observatory’s Skywatch Line for Friday, March 17, through Sunday, March 19, written by Sam Salem.

On Friday, Sun rises at 7:04am and sets at 7:05pm; the 77% illuminated Waning Gibbous Moon rises at 11:12pm on preceding day, reaching transit altitude of 33 degrees south at 4:34am and sets at 9:52am. The Spring Equinox comes on Monday at 6:29am EDT.

Venus is the first star-like object to shine into the evening twilight. You might be able to see Venus as soon as a few minutes after sunset. Venus will fall sunward to pass in between the Earth and Sun on March 25. Day by day, Mercury will climb upward from the setting Sun. By the month’s end, Venus will have left the evening sky, while Mercury will be at its best evening apparition of the year. At early-to-mid evening, look eastward to see Jupiter, the sky’s second brightest planet in the night sky after Venus. On Saturday, Jupiter’s moon Io, barely off Jupiter’s western limb, disappears into eclipse by Jupiter’s shadow around 10:24pm. A small telescope will show it slowly fade away. In a dark sky, try to locate constellation Corvus near Jupiter and Spica, the brightest star in the constellation Virgo, the Maiden. Use the waning Moon to guide you to the star Antares and the planet Saturn over the next several mornings.

The dim constellation Cancer is on the traditional divide between the winter and spring sky. It lies between Gemini to its west and Leo to its east. Constellation Cancer holds the Beehive Star Cluster, M44, in its middle. The Beehive is one of the nearest open clusters to the Solar System. Under dark skies the Beehive Cluster looks like a nebulous object to the naked eye. It was among the first objects that Galileo studied with his telescope. Look for it a little less than halfway from Pollux, in Gemini to Regulus, in Leo.

Orion has moved and turned considerably in the last few weeks. Depending on latitude, the farther south, the longer Orion can be seen in the night sky. For our area and for most of the United States, Orion will be gone by the time of the summer solstice, in June.

On March 17 1899, William Henry Pickering observed Phoebe, the ninth moon of Saturn, as a very faint object on a photographic plate. taken in August a year before. The image was captured in August 1898 on a 14 x 17 inches plate exposed for two hours in the telescope at the Harvard station near Arequipa, Peru.

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