This is Dudley Observatory’s Skywatch Line for Friday, February 10, through Sunday, February 12, written by Sam Salem.
On Friday, the Sun rises at 6:59am and sets at 5:21pm; full Moon occurs at 7:33pm, rising at 5:14pm and setting at 7:15am on the following day. The full Moon will pass through the Earth’s faint penumbral shadow for a portion of Friday night. A penumbral lunar eclipse occurs when the Moon is full and the Sun, Earth and Moon are imperfectly aligned in a straight line. It takes place when the Moon moves through the faint, outer part of the Earth’s shadow, the penumbra. It is often hard to differentiate between a typical full Moon and a penumbral eclipse of the Moon as the uncovered part of the Moon receives the same amount of sunlight as usual. The ideal spot to watch this penumbral eclipse is from Europe, Africa, Greenland and Iceland because the whole eclipse from start to finish occurs at late night in a dark sky. For the most of North America, the Moon will be in eclipse at moonrise, which is around sunset on Friday. The evening twilight will obscure the beginning of the eclipse. The penumbral eclipse begins at 5:34pm, reaching its maximum at 7:43pm, and ending at 9:53pm EST.
Venus is as high up at dusk as it is going to get during apparition next week. Venus, the evening “star”, at magnitude –4.8, can be seen before sunset. Mars shares the same area of sky glowing at magnitude 1.2 standing out among the stars of Pisces.
Jupiter at magnitude –2.2 rises around 11pm. The best viewing opportunity of Jupiter’s Great Red Spot occurs when the Red Spot is on the meridian, around 1:29am, on Saturday morning. The meridian is an imaginary line that joins north and south and passes through the center of the planet’s disk. The Red Spot can be viewed effectively up to an hour before or after its meridian crossing. The Red Spot is a giant storm that has been churning in Jupiter atmosphere for hundreds of years. The Red Sport feature is easy to detect even in a small scope. Larger scopes show it more vividly.
On Saturday night, the Moon closely partners with Regulus, the brightest star in the constellation Leo, the Lion. They climb highest up for the night around 1:00am and sit low in the west as darkness gives way to dawn on Sunday. Watch the Moon pass in front of the constellation Leo over the next few days. A series of monthly lunar occultation of Regulus started on December 18, 2016, and will continue to take place until April 24, 2018.
On February 10 1958, the MIT engineers at Lincoln Laboratories bounced Radar signals off planet Venus. The experiments were conducted during an inferior conjunction with Venus. The return echoes were distinguished from the background noise using digital signal processing. The results led to a more precise determination of the value of the astronomical unit (AU), the Earth’s mean distance to the Sun. A new value of the AU, 149,600,000 km was adopted at a general meeting of the International Astronomical Union in Hamburg in 1964.