Thursday, September 5, 2019

The Ellensburg, WA sky for the week of September 7, 2019

Saturday:  Saturn remains about half a fist held at arm’s length to the upper left of the Moon throughout the night. Look for them in the southern sky at sunset. They will be moving closer together in the sky as they both set as viewed from the United States. People in parts of Australia, Indonesia, and Papua New Guinea will actually see the Moon occult or block Saturn. You might think, “big deal, the Moon blocks a planet.” But carefully timed occultations such as this give astronomers a means to precisely study lunar topography.

Sunday: “Excuse me, do you have the time?”
“No, but the Big Dipper does.”
You can use the orientation of the Big Dipper to tell time with a precision of about 15-30 minutes. First, find the two stars at the far end of the Big Dipper cup, the stars that do not touch the handle. Draw an imaginary line segment starting at the North Star and passing through the two Big Dipper cup stars. Now, draw a big circle around the North Star. Your circle is a 24-hour clock. Number the circle from 0 hours at the top, counterclockwise to 12 hours at the bottom of the circle, and back up to 24 hours at the top. (O hours and 24 hours are the same on this clock because the day is 24 hours long.) The hour number on the big circle closest to where your imaginary line intersects this circle is called your raw time. Due to the location of the Big Dipper compared to the rest of the stars, the time nearest the intersection (the raw time) is correct for March 6. For any other night, subtract two times the number of months the current date is after March 6 from the raw time. For example, let’s say the imaginary line between the North Star and the Dipper stars is pointed to the right. That means the raw time is 18 hours or 6 p.m. If you made this observation on October 6, which is seven months after March 6, you would subtract two times seven or 14 hours from the raw time.  Thus, the time for November 6 is 18 hours minus 14 hours or 4 hours. In other words, 4 a.m. Don’t forget to convert for daylight savings time if needed. For a more complete explanation on how to do the Big Dipper clock math, go to http://goo.gl/02HmA. If you prefer a more visual tool, and a fun project to do with your kids, there is a simple “star clock” template and instructions at http://goo.gl/SFKrE. Use this paper star clock whenever you watch is broken.

Monday: The planet Neptune is on the opposite side of the Earth as the Sun is, meaning it is at its brightest and easiest to see. Of course, “bright and easy” is relative because you’ll still need binoculars to see it. Go out at 11:00 p.m. and  find Fomalhaut, the bright star a little less than one fist above the south-southeastern horizon. Then move your binoculars up about three binocular fields of view to the fairly bright star called Skat. Next continue to move up about one and a half binocular fields of view to the reddish star called Hydor, which is a little dimmer than Skat. Finally, move your binoculars one binocular field of view to the left to a Phi Aquarii, star that is a little dimmer than Hydor. Neptune is the dimmer point of light to the right of Phi Aquarii. Go back to this spot for the next few nights to watch Neptune move away from Phi Aquarii.

Tuesday: Had the script been written a little differently for a well-known Robin Williams movie, we might have heard Mr. Williams shout, “Goooood Morning Orion the hunter”. Orion is typically thought of as a winter constellation. But, it makes its first appearance in the early morning summer sky. The lowest corner of Orion’s body, represented by the star Saiph (pronounced “safe”), rises at 2 a.m., well before the Sun. By 6 a.m., Orion’s belt is nearly four fists above the south-southeastern horizon. 

Wednesday: In 1987, the rock group Def Leppard sang “Pour some sugar on me, in the name of love. Pour some sugar on me, come on fire me up”. In 2012, some European astronomers “found some sugar near stars, they were very young. Found some sugar near stars, out where planets formed.” Astronomers observed molecules of glycolaldehyde, a simple form of sugar, in the disk of gas and dust orbiting young binary stars. This is the first time astronomers have found this simple sugar so close to a star indicating that organic molecules can be found in planet-forming regions of stars. For more information, go to http://goo.gl/tfwy1.

Thursday: Next July, NASA will launch the Mars 2020 rover. Boring name, right? Well, NASA just launched a contest for K-12 students to name the rover. Go to https://mars.nasa.gov/mars2020/participate/name-the-rover/ for more information.The first helicopter in space will be hitching a ride on the rover. This helicopter, with blades that rotate at about 3,000 revolutions per minute, is a possible prototype for future missions to Mars and other Solar System bodies. Go to  https://youtu.be/oOMQOqKRWjU to see a test flight. Mars is too close to the Sun in the sky to be visible. By the end of September, it will pop out from the Sun’s glare.

Friday: Tonight's Full Moon is an un-supermoon because it is near apogee, its farthest distance from the Earth.


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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