Wednesday, June 1, 2016

The Ellesnburg WA sky for the week of 6/4/16

Saturday: Tomorrow morning, Mercury will be as far away from the Sun in the sky as it will get this orbital cycle. This "farthest away" point is known as the planet's greatest elongation. Tomorrow morning will be the best morning to observe Mercury for the next few weeks. Even this “best” viewing is not very good because Mercury is less than a half a fist above the east-northeast horizon at 4:30 a.m. Over the next few weeks, Mercury will move toward the Sun in the sky. By mid-July, it will be visible in the evening sky.

Sunday: The next sighting of the thin waxing crescent Moon marks the start of Ramadan on the Islamic calendar. Unlike the Gregorian calendar, which is based on the Sun, the Islamic calendar is based on the 29.5-day period of the Moon’s revolution around the Earth. That means that months on the Islamic calendar move forward by about 11 days each year. (Since the lunar month is about one day shorter than the Gregorian calendar month, each Islamic month moves ahead a little less than a day leading to the 11-day difference per year.) Therefore Ramadan falls on a different month from year to year. Adherence to the teaching of the Qur’an requires that Muslims fast during daylight hours. The requirement will be especially taxing this year because Ramadan includes the longest day of the year. There are many more hours of daylight this Ramadan than a Ramadan that falls in the Gregorian calendar month of December.
Another interesting aspect of Islamic months is that they start when the thin waxing crescent Moon is visible from your locale. For most of the world, that is June 6 but for part of South America, it’s June 5. For more information about the visibility of the crescent Moon, go to

Monday: As the weather warms up, people start thinking about swimming in a nice cool body of water. Recently, astronomers have discovered evidence an ocean about 20 miles beneath the surface of Saturn’s moon Enceledas. NASA’s Cassini probes measured variations in how the moon’s gravity pulled on the orbiting spacecraft. These variations can be explained by a large amount of liquid water under one section of the ice because liquid water is denser than an equal volume of ice. While you need a very large telescope to see Enceledas, Saturn is one and a half fists above the southeast horizon at 10 p.m.

Tuesday: Did you notice that really bright object near Saturn last night? That’s Mars, at its brightest and closest position for the year. Mars is two fists above due south at 11:30 p.m.

Wednesday: The bright star Spica is three fists above due south at 9:15 p.m. Try to make that your wishing star tonight, the first star you see.

Thursday: Summer is nearly here. How do I know? Because the days are very long. Because the temperature is rising. Because kids are getting out of school. Also, because the Summer Triangle is fairly high in the eastern sky at 10:30 p.m. Vega, the third brightest star visible from Ellensburg, is about five fists above the east horizon. Deneb, at the tail of Cygnus the swan is about three and a half fists above the northeast horizon. The third star in the triangle, Altair, in Aquila the eagle is two fists above the east horizon.
If you want to put somebody off, tell her or him to wait until Deneb sets. At Ellensburg’s latitude of 47 degrees, Deneb is a circumpolar star meaning it never goes below the horizon.

Friday: Jupiter is one fist to the upper left of the Moon at 10 p.m.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to

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