Friday, July 22, 2011

The Ellensburg sky for the week of 7/23/11

Saturday: The Southern Delta Aquarid meteor shower peaks for the next few nights and early mornings with the greatest concentration of meteors being visible Friday night and Saturday morning. Meteor showers are named after the constellation from which the meteors appear to originate. These meteors appear to come from a point in Aquarius near the star Delta Aquarii, also known as Skat. This point is about one and a half fists held upright and at arm’s length above the southeast horizon at 1 am tomorrow morning. You can follow this point throughout the night as it will remain a fist above Fomalhaut, the brightest star in that section of the sky. This year, the Moon will be near the new phase meaning visibility will be maximized. As you Mother might say, dress warm and sit in a comfortable chair for maximum enjoyment. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere.

Sunday: 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 10:14 p.m. It looks like a bright light on a pole on the north ridge because is only about one degree above the horizon.

Monday: Say "Cheese". 159 years ago this month, Vega, in the constellation Lyra the lyre, became the first star ever photographed. The photograph was done at the Harvard Observatory using the daguerreotype process. Vega is the third brightest nighttime star we can see in Ellensburg behind Sirius and Arcturus. Vega is nearly straight overhead at 11:00 tonight.

Tuesday: Hercules stands directly overhead this evening. Four moderately bright stars form a lopsided square that represents his body, while his head points southward. The monsters he has dispatched such as Hydra the water snake surround him.

Wednesday: The recently completed sequel to the musical “South Pacific” called “Viewing the South Pacific Sky” will be opening this morning on the island of Tahiti. Critics are raving about the remake of the song “Some Enchanted Evening with the lyrics “some enchanted evening, you may see an occultation, you may see an occultation across a crowded sky.” Just before sunrise this morning in Tahiti, the Moon will pass in front of Mars and block it from view. This is called an occultation. As viewed from Central Washington, Mars will be a couple finger widths to the lower left of the Moon at 5 a.m. and not be blocked by it.

Thursday: Saturn is one fist above the west-southwest horizon at 10 p.m.

Friday: It’s Friday night. You like to stay up late. Why not make it productive and look at the planet Jupiter and its largest moons. Jupiter is one fist above the east horizon at 1 a.m. tonight. With binoculars and a steady mount such as a tripod or the shoulders of a friend, you can see two to four of Jupiter’s Galilean moons.

Wait a minute. We got all the way to the end of the week with no Moon phase summary? How can that be? There are 29.5 days between the same Moon phase in two different cycles. That means about 7.5 days between the phases new, first quarter, full and last quarter. Since a week is seven days, there are some weeks in which none of the main phases occur. This week, the Moon was always in the waning crescent phase.

The positional information in this column about stars and planets is typically accurate for the entire week.

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