Sep 2

Sky Report: September 5 – 11

Four bright planets are out tonight, although not at the same time. In order of rising they are: Saturn, Jupiter, Mars, and Venus. Mercury is between the earth and sun and can’t be seen.

Saturn is everybody’s favorite planet when seen through a telescope. It’s low in the east as darkness falls. If you do have a telescope, have patience: wait to look at it until it has risen above the lowest and densest layers of our atmosphere, which distort its image, until perhaps around 10 p.m. I once looked at it through a 40-inch refractor (yes, 40) after it had just risen and I couldn’t make out the rings. Saturn rises 4 minutes earlier each day (a consequence of the earth’s motion around the sun) and that 10 p.m. becomes 8 p.m. in only a month. This isn’t the place to *describe* Saturn (Uncle Google can help you) but to advise you when and where to look. The nearly-full moon is 7° from Saturn on the 7th.

Jupiter rises next, following Saturn by precisely 2 hours, and it follows Saturn’s path across the sky. Like Saturn, and for the same reason, give it time to rise higher before examining it through a telescope, and like Saturn it rises 2 hours earlier each month. The nearly-full moon is 7½° from Jupiter on both the 10th and 11th, and those are great nights to see how far the moon moves around the earth in 1 day, using Jupiter as a reference.

By the way, the moon is full at 5 a.m. on the 10th. Jupiter is the brightest planet that can be near the full moon. Mars can be near the full moon too, but it’s never quite as bright as Jupiter. Venus is brighter than Jupiter, but it can never be near the full moon – can you figure out why? (The answer is left for the student.)

Mars rises 3 hours after Jupiter, which is around midnight. It’s still quite distant at 85 million miles, and telescopically its diameter is only 10 arcseconds. At its closest on December 1 – less than 3 months away! – it will be 51 million miles distant and 17 arcseconds in diameter. I can hardly wait.

Mars is in Taurus, near the orange star Aldebaran. They’re so close to each other that you’ll see them together in binoculars. Mars is closest to Aldebaran on the 7th when they’re 4¼ degrees apart, although they’re almost as close all week. Compare their brightnesses now; make a note and compare again in December, and note then how much brighter Mars is than Aldebaran. This is an opportunity for the attentive observer to see another kind of change in the sky. Also note their similar colors: which is oranger?

On the morning of the 5th, Venus rises 1 hour before the sun. It’s less than 1° from Regulus. Regulus is a bright star but Venus outshines it by 130 times! You won’t see Regulus so low in morning twilight.

Stellar Vista Observatory provides portable telescopes and tripod mounted binocular kits on loan for free to residents and visitors in Kane County. Enhance your enjoyment of the night sky! For details or to request a loan, visit or drop in to the Kane County Office of Tourism.

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 Send questions and comments to

About the Author:

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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