Wednesday, September 18, 2019

The Ellensburg, WA sky for the week of September 21, 2019


Saturday: At 8:00 p.m., Jupiter is one and a half fists held upright and at arm’s length above the so-th-southwestern horizon and Saturn is two fists above due south. It’s fun to see them with the naked eye (and to say the phrase “naked eye”) and enlightening to see them in a small telescope. But if you want to see detailed views of Saturn (https://tinyurl.com/y3twzqm3) and Jupiter (https://tinyurl.com/y2b7p5h2), follow the links or go to the Hubble Space Telescope website at https://www.spacetelescope.org

Sunday: Stuart Sutcliffe was the fifth Beatle. d’Artagnan was the fourth Musketeer. Ophiuchus is the thirteenth constellation in the Zodiac. The Zodiac consists of all the constellations that the Sun appears to line up with as the Earth’s celestial perspective changes throughout its annual orbit. You know twelve of the constellations in the Zodiac because they are the 12 horoscope signs. But the Sun also lines up with Ophiuchus for about two weeks every year. You can spend some time with Ophiuchus tonight. The center of the coffin shaped group of stars is three fists above due southwest at 8:30 p.m.

Monday: At 12:51 a.m. PDT, the center of the Sun crosses the celestial equator and passes into the southern sky. The celestial equator is an imaginary line that divides the sky into a northern and southern half. When the Sun is in the southern half of the sky, it appears to take a shorter path from rising to setting. It also does not get as high in the sky at noon. This leads to shorter days and longer nights. Since the Sun crosses the celestial equator today, there is an instant when it is equally in the northern and southern sky, called the north and south celestial hemispheres. This so-called “equal night” is given by the Latin word equinox. Thus, today is known as the Autumnal Equinox. However, the day and night are not of equal duration today. The sun rises at 6:50 a.m. and sets at 6:58 p.m. in the northern latitudes of the United States. Day and night are closest to equal duration on Wednesday.

Tuesday: The bright star Capella is about a half a fist above the north-northeastern horizon at 8:00 p.m.

Wednesday: To celebrate the start of school at Central Washington University today, you could take a quick trip to Mars. How about America’s desert Southwest? Not enough time? Then just look at some photos from… from…. Hmmm. The photos at https://goo.gl/Elx7O8 look like they could be from either place. The Murray Buttes region of Mars, where the Curiosity rover has been exploring, look a lot like the landscape of Utah. So much so that the Mars-based movie John Carter was filmed in the desert of southern Utah. Look for John Carter at your local video store. Listen to the soundtrack on your record player. Then take a Polaroid selfie of you enjoying each experience. Look for Mars just above the eastern horizon at 6:30 a.m.

Thursday: Regulus is about two finger-widths to the right of the waning crescent Moon at 6:00 am. They are two fists above due east.

Friday: “There’s water in them thar craters”, frozen water, that is. There has been speculation since the 1960s and indirect evidence since the 2000s of water on the Moon. Recently astronomers studied data from the Moon Mineralogy Mapper, the Lunar Orbiter Laser Altimeter, Lyman-Alpha Mapping Project, and Diviner Lunar Radio Experiment. The light reflecting off the bottom of craters near the lunar South Pole showed characteristics of light reflecting off pure ice in their labs. The water likely came from comet impacts or other solar system objects with trace amounts of water ice. For more information about this discovery, see https://goo.gl/P4zvtU

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 https://nightsky.jpl.nasa.gov/planner.cfm.

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