Stellar Vista Observatory Sky Report
John Mosley
Aug. 23 – 29
The Sky Report is presented as a public service by the Stellar Vista Observatory, a nonprofit organization based in Kanab, Utah, which provides opportunities for people to observe, appreciate and comprehend our starry night sky. Additional information is at www.stellarvistaobservatory.org. Send questions and comments to [email protected].
The first planet that appears tonight is brilliant Venus. Venus sits low in the west as the sky is growing dark and it sets about 90 minutes after the sun.
Jupiter and Saturn are rising but still low in the southeast as Venus is setting in the west and you can see both Jupiter and Saturn all night long. Both planets are traveling slowly westward against the background stars because we are passing them on an inside orbit. They’re actually moving eastward as they orbit the sun, but just as a slower moving car appears to briefly move backwards as you pass it, so too Jupiter and Saturn appear to move backwards as we pass them. Follow their motions night to night with binoculars.
And there is plenty to see with a telescope. You can see Jupiter’s four large moons with any telescope and even high-power tripod-mounted binoculars, and you can watch them change position night by night and even hour by hour. It’s especially interesting when a moon and its shadow cross the face of Jupiter.
For example, Io and its shadow both cross Jupiter from roughly 10 pm to midnight on Thursday. It’s hard to see Io because it’s a white moon against an off-white planet but you can see the tiny black shadow with high power, and you can watch it move across the face of Jupiter as Io orbits the planet. Google “Jupiter’s Moons Observing Tool” or use an app like SkySafari to know when such events will happen; they’re not rare. You’ll also see Jupiter’s major cloud belts which parallel its equator.
Turn a telescope to Saturn and you’ll see the magnificent set of rings. If your optics are good and the air is steady you’ll see the “Cassini Division”, a narrow gap which separates the inner and outer rings, and you can also see its large moon Titan. Titan orbits Saturn in two weeks so its position changes nightly. You can see where it is by using an app like SkySafari, or Google “Saturn’s Moons Observing Tool”.
If you don’t own a telescope you might borrow one from your local library or attend a public “star party” where a variety of telescopes will be pointed skyward, operated by amateur astronomers who will explain what you’re seeing. You can learn about upcoming star parties around Kanab by Googling “2021 Southwest Astronomy Festival”.