4 Sky Events This Week: Moon Points to Crab and Leo’s Heart

A mosaic by NASA’s Hubble Space Telescope of the Crab Nebula, a six-light-year-wide expanding remnant of a star’s supernova explosion.  Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)

Visit stunning stellar grave sites and watch the moon pair up with kings of the celestial jungle for a delightful starry tour this week in sky-watching.

The Moon and the Crab  

In the predawn hours of Tuesday, September 16, backyard telescope users can hunt down the sky’s most famous, and arguably best, example of a supernova remnant, thanks to the moon pointing the way.

Look for the faint Crab Nebula approximately 4 degrees above the moon, slightly less than the width of your fist held at arm’s length. The nebula is also easily found about 1 degree northwest from the star Zeta Tau, the gleam that marks the tip of the southern horn of the Taurus, the Bull.

This wide angle sky chart shows the eastern sky in the pre-dawn hours of September 16, 2014.  Credit: SkySafari
This wide-angle sky chart shows the eastern sky in the predawn hours of September 16, 2014. Credit: SkySafari

Despite the Crab Nebula intrinsically shining some 75,000 times brighter than our sun, it glows only faintly in the sky at magnitude 8.4. It is still not too difficult to spot with a run-of-the-mill 7 x 50 binocular from dark skies.

Current estimates put this stellar wreckage, the aftermath of a star explosion, at about 6,000 light-years away from Earth. Amazingly, after its massive progenitor star blew itself apart, it was actually seen in the sky in A.D. 1054 by Chinese astronomers.

This finder chart show the relative position of the Crab Nebula to the nearby star Zeta Tauri and the waning crescent moon on September 16, 2014. Credit: SkySafari
This finder chart show the relative position of the Crab Nebula to the nearby star Zeta Tau and the waning crescent moon on September 16, 2014. Credit: SkySafari

Swan Points to Dumbbell

After nightfall on Thursday, September 18, sky-watchers across mid-northern latitudes can look straight overhead and find the bright summertime constellation of Cygnus, the Swan.

Otherwise known as the Northern Cross, this bright stellar pattern is easy to spot this time of the year, even from light-polluted suburbs.  While the most prominent star in the group is Deneb, the second brightest, Albireo, marks the head of the Swan, or foot of the Cross.

Wide-angle sky chart showing bright constellation Cygnus, and its bright star Albireo pointing the way to the Dumbbell nebula, M27. Credit: SkySafari
This wide-angle sky chart shows bright constellation Cygnus and its bright star Albireo pointing the way to the Dumbbell Nebula, M27. Credit: SkySafari

Using binocular, scan just one field of view below Albireo (about 8 degrees) and you may notice what looks like the faint, tiny cloudlike spot known as the Dumbbell Nebula or Messier 27.

Shining at magnitude 7.3, it is an easy target for even small backyard telescopes. With its double-lobed shape, it looks a lot like its name implies.

 

The Dumbbell Nebula ­— also known as Messier 27 is a typical planetary nebula and is located in the constellation Vulpecula (The Fox). Credit: ESO
The Dumbbell Nebula, also known as Messier 27, is a typical planetary nebula and is located in the constellation Vulpecula (the Fox). Courtesy of ESO

The Dumbbell is a cloud of expanding gas and dust, the remains of the death of a sunlike star sitting about 1,700 light-years away.

Astronomers have not been able to pin down the exact age of the object, but they estimate that the progenitor star died sometime between 3,000 to 15,000 years ago.

This sky chart shows the moon parked next to Jupiter before dawn on September 20, 2014.  Credit: SkySafari
This sky chart shows the moon parked next to Jupiter before dawn on September 20, 2014. Credit: SkySafari

 

The Moon and Jupiter

Early risers on Saturday, September 20, may see the waning crescent moon park itself next to brilliant Jupiter. The stunning pair will appear only about 5 degrees apart.

It is amazing to think that while light takes only 1.3 seconds to bounce off the lunar surface and hit your eye, the photons of light reflecting off the upper cloud deck of Jupiter takes a stately 49.6 minutes to reach us.

The Moon and Regulus

By the next morning on Sunday, September 21, the moon will have sunk lower in the East and by this time join the brightest star in the constellation, Leo (the Lion).

Skychart showing the moon next to Regulus in the pre-dawn sky on September 21, 2014. Credit: SkySafari
This sky chart shows the moon next to Regulus in the predawn sky on September 21, 2014. Credit: SkySafari

Regulus, known to ancient astronomers as Cor Leonis—the heart of the lion—lies some 79 light-years away from Earth.

This bright blue-white star is so far from Earth that the light we see it by tonight left on its journey in the same year that Amelia Earhart became the first person to fly solo from Hawaii to California; T.E. Lawrence (Lawrence of Arabia) died in a motorcycle accident; and the U.S. unemployment rate was hovering around 20 percent—in 1935.

Happy hunting!

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Changing Planet

Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.