The Ellensburg sky for the week of 6/5/10

Saturday: In 1979, the group Foreigner recorded the song “Head Games”. They could have been singing about the constellations Hercules and Ophiuchus when they said “head games, it’s just you and me baby, head games, I can’t take it anymore” because the heads of these two constellations have been right next to each other in the nighttime sky for all of human history. Each head is represented by a star bears an Arabic name that means "the head." In Hercules, it's Ras Algethi (head of the kneeler); in Ophiuchus, Ras Alhague (head of the serpent charmer). At 11 p.m., Ras Alhague, the brighter of the two, is a little more than four fists held upright and at arm’s length above the southeast horizon. Ras Algethi is about a half a fist to the upper right of Ras Alhague.

Sunday: For the next few months, Uranus and Jupiter will be neighbors in the sky. For the next couple of months, you’ll have to either get up early or stay up late to see them. At 4:30 a.m., they are two and a half fists above the southeast horizon. Jupiter is the brightest point of light in the area. You’ll need binoculars to see dim Uranus just to the upper left of Jupiter. This morning, Jupiter and Uranus are joined by the Moon

Monday: Mars is near Regulus in the sky for the next few nights. Tonight, Regulus, the dimmer of the two is less than a pinky width to the lower right of Mars. They are three fists above the west-southwest horizon tonight.

Tuesday: Mizar is a well known binary star in the constellation Ursa Major. You can find it at the bend in the Big Dipper handle, nearly straight overhead at 10 p.m. tonight. Its name is Arabic for waistband. Mizar has an optical double called Alcor which is less than a pinky width away and can easily be seen with the naked eye. Optical doubles are stars that are close together in the sky but do not orbit a common center of mass as true binary stars. Not wanting to deceive sky gazers who call Mizar a binary star, two stars that DO orbit a common center of mass, Mizar actually is a binary. It was the first binary star system discovered by telescope. Mizar A and Mizar B are about 400 astronomical units apart from each other and about 80 light years from Earth. 400 astronomical units is about 10 times the distance between the Sun and Pluto.

Wednesday: Saturn is four fists above the southwest horizon at 10 p.m.

Thursday: Venus lines up with the Gemini twins, Pollux and Castor, for the next couple of nights. Tonight Venus is about one fist above the west-northwest horizon. Pollux, the brighter of the “twins” is a half a fist to the right of Venus and Castor is another half fist to the right of Pollux.

Friday: Vega, probably the second star you’ll see tonight, is four fists above the east-northeast horizon at 9:30 p.m. Last week I wrote that Arcturus, high in the southeast sky, is most likely the first star you’ll see tonight. You DO remember me writing that, don’t you?

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.