Driftless Dark Skies: Twinkling Stars

Graphics created with Starry Night software. View 1 looks NNW at 5:30pm on Nov 10 to see Arcturus and Capella. View 2 is looks ESE at 10:30pm on Nov 10 to see Sirius.

Driftless Dark Skies: Twinkling Stars

November is a great month to watch stars twinkling in the autumn sky. And there are three that especially attract our attention. You can enjoy the sparkly rainbow colors with your unaided eyes, but bring along your binoculars to enjoy an even better light show.

Look low in the WNW during twilight to see Arcturus. It’s the brightest star in that part of the sky, one of the first to emerge after sunset, and is visible until it sets around 6:15 (Nov 10). Arcturus is the second-brightest star visible at our latitude. Its name is Greek for “guardian of the bear.” You can spot the Great Bear containing the familiar Big Dipper to the right of Arcturus skimming the horizon low in the NNW. Be sure to notice how the three stars in the tail of the bear/handle of the dipper “arc to Arcturus”.

While Arcturus is setting, Capella is rising in NNE. It’s the fourth-brightest star visible at our latitude. Capella is nicknamed “the goat star” or little she-goat in Latin. While you are admiring its flashing colors with your binoculars, slew just to the right of Capella to see three dimmer stars known as “the kids”. Mother and offspring will all fit in a single field of view. Like Arcturus, Capella is a close neighbor to our Sun.

Later in the evening around 10:30 (Nov 10), watch for Sirius rising in ESE. The three bright stars of Orion’s Belt are all in a row and above the horizon by 8:30. Follow their line down to predict where Sirius rises. If 10:30 is getting late for stargazing, just remember that Sirius rises four minutes earlier every day and will be rising around 9:10 by the end of the month. Sirius is the brightest star of the night sky and is nicknamed “the dog star”. It’s part of a constellation called Canis Major/Big Dog who follows on the heels of Orion the Hunter.

Twinkling is a great way to tell planets from stars. Three planets are visible this month: Jupiter is very bright in the east in the evening, Saturn is bright in the south in the evening, and Venus is brighter than any star in the east in the morning. Notice how they glow with a steady light even when they are low on the horizon.

So why are stars scintillating like such crazy jewels? The starlight we see in 2023 left Sirius in 2015, Arcturus in 1986, and Capella in 1980. It was a steady light as it traveled tens of trillions of miles through space. Only for the last dozen or so miles does it pass through our turbulent atmosphere with its different temperature layers and gets shifted and refracted into different colors. When stars are low in the sky, their light passes through more atmosphere and twinkles all the more. Hope you are able to get out and enjoy them this fall!

John Heasley is an astronomy educator and stargazer who enjoys connecting people with the cosmos. He volunteers with NASA/JPL as a Solar System Ambassador , with the International Dark-Sky Association as an Advocate, and the International Astronomical Union as a Dark Sky Ambassador. For more information about stargazing in southwest WI, like Driftless Stargazing LLC on Facebook and find out whenever there’s something awesome happening in the skies.