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Tonight

Moon east of Spica, west of 2 planets at nightfall August 30

Moon moving toward Mars and Saturn on August 30, joins up with Mars and Saturn on August 31 and moves on toward Antares on September 1

Moon moving toward Mars and Saturn on August 30, joins up with Mars and Saturn on August 31 and moves on toward Antares on September 1.

As darkness falls around the world on August 30, look for the star Spica to the west of tonight’s waxing crescent moon. Planets Mars and Saturn are to the east of tonight’s moon. Remember, west is in the direction of sunset.

How far is a light-year?

The Orion Nebula, 1,500 light years from Earth. Image credit: NASA/JPL-Caltech/STScI

The Orion Nebula, 1,500 light years from Earth. Image credit: NASA/JPL-Caltech/STScI


Here’s your FAQ for this Friday ….

Light is the fastest-moving stuff in the universe. It travels at an incredible 300,000 kilometers (186,000 miles) per second. That’s very fast. A light-year is the distance light travels in one year. How far is that?

Moon near star Spica, heading for Mars and Saturn, on August 29

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As soon as darkness falls on August 29, look low in the southwest sky for the slender waxing crescent moon and the star Spica. Over the next few days, at nightfall, watch for the moon to move away from Spica and toward the planets Mars and Saturn. Be sure to catch the moon and Spica as soon as darkness falls, for the two will follow the sun beneath the horizon shortly thereafter.

Star of the week: 61 Cygni is the Flying Star

The orbital motion of component B relative to component A as seem from Earth as well as the true appearance from face-on view. The time steps are approximately 10 years.  Illustration via Wikimedia Commons

The orbital motion of component B relative to component A as seem from Earth as well as the true appearance from face-on view. The time steps are approximately 10 years. Illustration via Wikimedia Commons

This star, 61 Cygni isn’t among the brightest stars. In fact, it takes some effort just to find it, because it is not much brighter than the faintest stars visible to the unaided human eye. It is, however, among the most important of stars visible without optical aid. It has one of the largest proper motions – that is, sideways motions along our line of sight – of any star in our sky. Its large proper motion has given 61 Cygni the nickname Flying Star. Follow the links inside to learn more.

Moon and star Spica low in west after sunset August 28

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Look westward as soon as darkness falls on August 28 to catch the slender waxing crescent moon fairly close the horizon. That bright star close to the moon is Spica, the brightest in the constellation Virgo the Maiden. Don’t delay, though, when looking of the moon and Spica, especially if you live at northerly latitudes, for the twosome will follow the sun beneath the horizon by early evening.

No double moon on August 27

This image is circulating on Facebook, with the claim that Mars will appear as big and bright as a full moon on August 27, 2013.  It's a hoax.  Don't believe it.  Mars never appears as large as a full moon in Earth's sky.

This image sometimes circulates on Facebook, with the claim that Mars will appear as big and bright as a full moon on August 27, 2014. It’s a hoax. Don’t believe it. Mars never appears as large as a full moon in Earth’s sky.

The famous double moon on August 27 hoax has come through like gangbusters this August. No one expected that! This hoax is now 11 years old. Still, clearly, not everyone knows it’s a hoax. Google searches have made this post the most popular on our site for the past week. An email must be circulating – somewhere, social media must be buzzing – with the suggestion that – on August 27, 2014 – Mars will appear as large as a full moon in Earth’s sky. And that is just not true.

Will you catch the moon near Mercury after sunset tonight?

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Our sky chart shows the moon and the planet Mercury as they appear in North America, about 35 to 40 minutes after sunset. For the most part, the thin waxing crescent moon and Mercury sit too close to the glare of sunset to be visible from mid-northern latitudes and farther north. These two worlds will be hard to spot after sunset at northerly latitudes, even in binoculars.

People in the Southern Hemisphere should have an easier time catching the young moon and Mercury after sunset on August 27. For example, At Rio de Janeiro, Brazil, Mercury sets about one and one-quarter hours after sunset, and the moon sets about 2 hours after the sun. At Philadelphia, Pennsylvania, on the other hand, Mercury sets less than 45 minutes after the sun, and the moon sets about 50 minutes after sunset.

Messier 8 is the Lagoon Nebula

Scott MacNeill captured this beautiful photo of M8 in August 2014.

Scott MacNeill captured this beautiful photo of M8 in August 2014. He wrote, “Here’s a fantastic capture of M8 – The Lagoon Nebula I shot at Frosty Drew Observatory in Charlestown, Rhode Island, USA … I focused on M8 for a while as it was looking so sexy!”

The Lagoon Nebula, also known as M8 or Messier 8, is a large gas cloud within the Milky Way Galaxy, barely visible to the human eye under good conditions. It appears a few degrees above and to the right of the Teapot asterism in the constellation Sagittarius. Visually about three times the size of the full moon, the Lagoon Nebula is the largest and brightest of a number of nebulosities in and around Sagittarius. Follow the links inside to learn more.

Orion the Hunter and Sirius the Dog Star

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The first hints of the changing of the seasons can be seen in the predawn and dawn sky: Orion the Hunter and Sirius the Dog Star. The very noticeable constellation Orion the Hunter rises before dawn at this time of year, and Sirius follows the Hunter into the sky at or close to dawn. Orion will become visible in the evening by winter, but presently the Hunter lords over the southeastern sky at dawn’s first light.

Everything you need to know: Harvest Moon 2014

Tonight's sunset and moonrise - September 19, 2013 - as seen by EarthSky Facebook friend Andy Somers in Noumea, New Caledonia.  One of the characteristics of the Harvest Moon is that it rises around the time of sunset for several evenings in a row.  Thank you, Andy.

Harvest Moon sunset and moonrise – September 19, 2013 – as seen by Andy Somers in Noumea, New Caledonia. One of the characteristics of the Harvest Moon is that it rises around the time of sunset for several evenings in a row. Thank you, Andy.

The moon will return to the evening sky this week, waxing toward full. Next full moon – night of September 8-9, 2014 – is the Harvest Moon.