Friday, July 24, 2015
The Ellensburg WA sky for the week of 8/1/15
Saturday: In Scotland, August 1 was known as Lammas, the festival of the first wheat harvest of the year. You can remember this by looking at Spica, named after the Latin word for “ear of wheat”, one fist held upright and at arm’s length above the west-southwest horizon at 9:30 p.m. August 1 is known as a cross-quarter day, a day approximately half way between an equinox and a solstice.
Sunday: If you want to show your loved ones a celestial sign that they should hang up their clothes, show them Brocchi's Cluster, commonly known as the Coat Hanger cluster because of its resemblance to an upside down coat hanger. The cluster is six fists above the southeast horizon at 10:30 p.m., midway between Altair and Vega, the two brightest stars in the Summer Triangle. You'll need binoculars to make out the shape. First find Altair four fists above the southeast horizon. Slowly move your binoculars up toward Vega. You will run into the coat hanger along the way. And while you are at it, put away your shoes.
Monday: Regulus, Jupiter, and the elusive Mercury make a straight line in the sky for the next three nights. Regulus and Jupiter stay close together, just above the west-northwest horizon at 9:00 p.m. Mercury is a half a fist to the right of Jupiter. On Tuesday and Wednesday, Mercury moves closer to the pair.
Tuesday: It’s a moonless August morning. The first remnant of dawn has not appeared yet. Suddenly, you notice a large softly radiant pyramid of light in the east sky. The base of this ghostly triangle is along the east horizon and the peak stretches two or three fists held upright and at arm’s length above the horizon about two hours before sunrise. Don’t be scared. It’s not really a ghost. It is an effect called the zodiacal light. This light comes from sunlight reflecting off dust grains in our solar system. The effect is the most visible when the band of constellations called the zodiac makes a steep angle with the horizon. You need a clear dark sky with no haze or light pollution to see the zodiacal light. At its brightest, the zodiacal light rivals the light of the central Milky Way. This is one of the best times of year to see the zodiacal light in the morning.
This is also one of the best times of the year to see meteors. The Perseid meteor shower peaks early next week. But you should see increased meteor activity later this week just below the W of the constellation Cassiopeia. This point is about two and a half fists held upright and at arm’s length above the northeast horizon at 11 p.m. By dawn, this point is about seven fists above the northeast horizon.
Wednesday: Do you want an easy way to find due north? A compass points to magnetic north, which is a few degrees off of true geographic north. Well, tonight’s your night. Capella, the brightest star in the constellation Auriga the Charioteer, is due north at exactly 9:23 p.m. It looks like a bright light on a pole on the north ridge because is only about one degree above the horizon.
Thursday: Saturn is two fists above the southwest horizon at 10 p.m.
Friday: Mars is finally escaping the glare of the Sun, showing up a half a fist above the east-northeast horizon at 5 a.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 http://nightsky.jpl.nasa.gov/planner.cfm.