Thursday, September 8, 2022

The Ellensburg, WA sky for the week of September 10, 2022

Saturday: Watch the Moon move closer to Jupiter throughout the night. When they rise at about 8:00 p.m., Jupiter is about one fist to the left of the Moon. At midnight, Jupiter is a little more than a half a fist to the upper left of the Moon in the southeastern sky. By 6:00 a.m. tomorrow morning, Jupiter is less than a half a fist above the Moon, low in the west-southwestern sky. If you’d like the challenge of seeing a planet in the daylight, wait another hour until 7:00 a.m. First find the Moon very low in the western sky. Use binoculars to look at the Moon, making sure the Moon is in the lower part of your field of view. Jupiter will be above the Moon, in about the middle of your field of view. Then move your binoculars away and look right above the Moon with your naked eyes. You may be able to see Jupiter.

Sunday: “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.

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: At 11:00 p.m., Saturn is two and a half fists above due south, Jupiter is three fists above southeast, and Mars is less than a half a fist above the east-northeastern horizon.

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: Neptune is in opposition tonight. Opposition doesn’t mean that Neptune disagrees with everything. It means that it is on the opposite side of the Earth as the Sun. When an object is in opposition, it is at its highest point in the sky during the darkest time of the day. Thus, opposition is typically the best time to observe a planet. Neptune is a little more than three fists above the southeast horizon at 11:00 p.m. It is one fist to the right of bright Jupiter.

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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