Wednesday, September 6, 2023

The Ellensburg, WA sky for the week of September 9, 2023

Saturday: “You know Aries and Cancer and Draco and Libra. Leo and Pisces and Virgo and Hydra. But, do you recall, the pointiest asterism of all? Triangulum, the three sided asterism, had a very pointy shape. And if you didn’t know it, you would say it poked an ape.” Sorry. Some stores have started sending out their Christmas catalogs and that has put me in the mood to modify some Christmas songs. Anyway, Triangulum is a small constellation between the more prominent Andromeda and Aries. Its main feature is a skinny triangle oriented parallel to and nearly four fists held upright and at arm’s length above the eastern horizon at 11:00 p.m.

Sunday: Arcturus is nearly two and a half fists above the western horizon at 9:00 p.m.

Monday: Fomalhaut, the southernmost bright star visible from the northern USA, is one fist above the south-southeastern horizon at 11:00 p.m. In 2008, Fomalhaut and its surroundings became the first star system with an extrasolar planet to be directly imaged. See the family photo at https://apod.nasa.gov/apod/ap081114.html.

Tuesday: While many people think they need a telescope to enjoy looking at the night sky, some objects actually look better through binoculars. Open star clusters are one of those types of objects. M39, the 39th object in Charles Messier’s catalog, is straight overhead at 11:00 p.m. This open star cluster contains about 30 stars in a region about seven light years across and a thousand light years away. A quick trigonometry calculation shows that the cluster is about the same size as the full moon in the night sky. Read more about M39 at https://stardate.org/radio/program/2022-09-04.

Wednesday: Jupiter and Saturn are in the eastern sky tonight at 10:00 p.m.. Saturn is two and a half fists above the south-southeastern horizon and Jupiter is one fist above the eastern horizon. Astronomers discovered volcanoes spewing water vapor on Saturn’s moon Enceladus back in 2005. Just two years ago, scientists published findings of similar activity on Jupiter’s moon Europa. It’s not possible to see Enceladus with a small telescope. But you can see Europa using a small telescope. If you look at 10:00 p.m., you’ll see all four large moons: three on one side and Callisto on the other, about four Jupiter diameters from Jupiter. For more information about Europa’s geysers, go to https://earthsky.org/space/europa-water-vapor-geysers-goddard.  

Thursday: Earlier this week, you read about Fomalhaut, the second brightest star with a planet. The brightest star known to have a planet is Pollux, in the constellation Gemini. (First vs. second brightest is meaningless here because they are nearly identical in magnitude, 1.15 vs. 1.16.) Pollux is four and a half fists above due east at 5:30 a.m., right below its “twin” star Castor. Read more about Pollux at https://goo.gl/cL5t9p.

Friday: Even though tomorrow is Saturday, it is a good morning to get up early. At 6:00 a.m., Mercury is a half a fist above the eastern horizon. The bright star Regulus is nearly a fist and a half above the eastern horizon. Venus, the brightest point of light in the sky, is two and a half fists above the east-southeastern horizon.

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.

No comments: