May 9

Sky Report: May 10 – May 16

Graphic created with SkySafariAstronomy.com

This is the best week of the entire year to see the elusive planet Mercury as it achieves it’s greatest angular distance from the sun, 22°, on the 17th. You should easily see it without binoculars, but you do need a low northwestern horizon, important to see Mercury but essential to see Venus just below.

30 minutes after sunset the sun is only 5° below the horizon while Venus and Mercury are 5° and 14° respectively above the horizon. If you can see clear down to the geometric horizon, you’ll see brighter Venus first and then fainter Mercury above it.

Especially good nights to look are the 12th, when the very thin crescent moon is a scant 1½° from Venus, the closest they will come this year, and the next night when the moon is 4° to the upper left of Mercury. Both nights the moon will be the slimmest of crescents and won’t be obvious; use binoculars.

After this week Mercury rapidly leaves the evening sky – you can watch it descend night-by-night — but Venus very slowly increases its distance from the sun, sets later, and become easier to see. Watch nightly; can you estimate the date when Mercury will pass Venus?

Mars is 30° above and to the left of Mercury, in the middle of Gemini the Twins. The moon joins Mars on the 15th when it’s less than 2° from Mars in one of the year’s closer conjunctions. The moon approaches Mars as the evening progresses and they’re closest as they set, so you can actually watch the moon approach Mars. The moon is many times brighter than Mars which is no longer especially bright. Mars is 800 times more distant than the moon.

Put these moon-conjunction dates in your calendar so you don’t forget; they won’t repeat. In all cases both objects are visible together in binoculars.

Two other planets are visible tonight, making 5 in total, and they are Jupiter and Saturn in the morning sky. Look low in the southeast between 1 and 2 hours before sunrise. Jupiter is brilliant while Saturn to the right, or west, is 1/13th as bright. How late in the morning as the sky brightens in morning twilight can you still see Jupiter? With binoculars you should see it until sunrise.


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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