Aug 31

Sky Report August 31 – September 6


The moon is full on the 1st – if you live in Utah. It’s full on the 2nd if you live in Chicago. Why the difference? Start by asking “for how long is the moon full?” The answer is the same as for the question “how long is it noon” – just an instant. The moon is full at 11:23 PM MDT on the night of the 1st, so it’s full on the 1st for people in Mountain and Pacific Time Zones and farther west, but if you’re in the Central Time Zone that same instant is 12:23 AM on the morning of the 2nd. And it’s full on the 2nd for people in time zones farther east. We think of the moon as being full for an entire night, and for practical purposes it is, but for almanac purposes it’s full for just an instant. That instant is 11:23:25 PM on the 1st, MDT, to be precise. That’s the instant when the moon is directly opposite the sun in the sky.

Turning to planets, you’ll find Jupiter and Saturn a third of the way up the southern sky as the sky grows dark. Jupiter is brighter than any star, and Saturn is a short distance (8°) to the left of Jupiter; Saturn is as bright as the brighter stars. Ten-power binoculars on a tripod will show the four moons of Jupiter but you’ll need a 30-power or better telescope to see the rings of Saturn. Both planets are in eastern Sagittarius.

Mars rises at 10 PM and is at its highest and due south at 4:30 AM. Like Jupiter, Mars is brighter than any star, so you can’t miss it. The moon passes very close to Mars on the night of Saturday the 5th.

Venus is the brightest planet and it rises at 3:30 AM. You can see it well into morning twilight and even after sunrise if you know precisely where to look. Immediately above Venus are the stars Castor and Pollux in Gemini and to the right of Venus is the star Procyon in Canis Minor, the Small Dog. Venus is in Gemini through the third and then in Cancer – a constellation without bright stars.

Beginning with this Sky Report I’ll recommend websites and apps that are particularly useful. These two plot very nice customizable charts of the night sky, and of course they’re free:
https://skyandtelescope.org/interactive-sky-chart/ and https://www.planetary.org/night-sky.


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 John@StargazingAdventures.org.

About the Author:

John Mosley
John Mosley was Program Supervisor of the Griffith Observatory in Los Angeles for 27 years and is the author of “Stargazing for Beginners” and “Stargazing with Binoculars and Telescopes”. He and his wife live in St. George where he continues to stargaze from his retirement home while serving on the advisory committee for Stellar Vista Observatory.

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