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August 28-September 4, 2009: Thuban, the Hercules Cluster, and the Veil Nebula

Michael Bakich — Fri, 28 Aug 2009 20:30:00 GMT

Each week, Astronomy magazine Senior Editor Michael Bakich, a master at explaining how to observe, posts a podcast about three objects or events you can see in the sky.

In each episode, Michael highlights:

One object you can see without any optical aid
One object you can see with a small (4-inch) telescope
One object you can see with at least an 8-inch telescope

Targets for August 28-September 4, 2009

Binoculars:

Small telescope:

8-inch or larger telescope:

The weekly observing podcast is available to registered members of Astronomy.com. The podcast remains FREE, so please register with the site to make sure you don't miss an episode!

Listen to this week's podcast.

This week's podcast is brought to you by Celestron — one of the world's leading designer and manufacturer of high-quality optical equipment. Learn more about Celestron and their products at www.Celestron.com.

June 26-July 3, 2009: The Keystone, globular cluster M10, reflection nebula NGC 6726

Michael Bakich — Thu, 25 Jun 2009 19:18:00 GMT

Each week, Astronomy magazine Senior Editor Michael Bakich, a master at explaining how to observe, posts a podcast about three objects or events you can see in the sky.

In each episode, Michael highlights:

One object you can see without any optical aid
One object you can see with a small (4-inch) telescope
One object you can see with at least an 8-inch telescope

Targets for June 26-July 3, 2009

Naked eye:

Small telescope:

8-inch or larger telescope:

The weekly observing podcast is available to registered members of Astronomy.com. The podcast remains FREE, so please register with the site to make sure you don't miss an episode!

Listen to this week's podcast.

June 5-12, 2009: Variable star R Coronae Borealis, open cluster NGC 6124, and globular cluster NGC 6144

Michael Bakich — Thu, 04 Jun 2009 15:57:00 GMT

Each week, Astronomy magazine Senior Editor Michael Bakich, a master at explaining how to observe, posts a podcast about three objects or events you can see in the sky. In each episode, Michael highlights:

One object you can see without any optical aid
One object you can see with a small (4-inch) telescope
One object you can see with at least an 8-inch telescope

Targets for June 5-12, 2009
Naked eye: Variable star R Coronae Borealis
Small telescope: Open cluster NGC 6124
8-inch or larger telescope: Globular cluster NGC 6144

Starting June 4, the weekly observing podcast is available to registered members of Astronomy.com. The podcast remains FREE, so please register with the site to make sure you don't miss an episode!

Listen to podcast.

May 29-June 5, 2009: Star known as La Superba, globular cluster M80, and Abell 1656

Michael Bakich — Thu, 28 May 2009 17:00:00 GMT

Loyal podcast listeners,

Starting June 4, Michael Bakich's weekly observing podcast will be available to registered members of Astronomy.com. The podcast remains free, so please register with the site to make sure you don't miss an episode!

We now return to our regularly scheduled program...

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Here is the transcript for my podcast about how to see the star known as La Superba, globular cluster M80, and Abell 1656 this week.

Check out the Astronomy.com's interactive star chart — StarDome — to see an accurate map of your sky. It'll help you locate some of this week's key targets. Astronomy magazine subscribers have access to a slew of cool functions with StarDome PLUS.

Each week, I highlight three different night-sky targets for you to see:

One object you can find with your naked eyes or through binoculars
One object to find with a small telescope
One deep-sky object to find with an 8-inch or larger telescope for you avid astronomers

--Start transcript--

Superb!
This week’s first target is one of the reddest stars in the sky. It’s official astronomical designation is Y Canum Venaticorum, but observers usually call it La Superba.

It received its common name from Italian astronomer Angelo Secchi. The star’s color so impressed him that he christened it “the superb one,” or La Superba.

Astronomers classify La Superba as a semi-regular variable star. That means most of the time the star’s brightness varies between a peak of magnitude 4.8 and a low of magnitude 6.3. It takes 160 days to go from one peak to the next … usually.

La Superba has a surface temperature near the minimum for stars, about 2,800 kelvins. (That’s about 4,600° Fahrenheit.) Compare that to the temperature at our Sun’s surface, which is 5,800 K (10,000° F).

La Superba also is a carbon star. Carbon compounds like soot accumulate in the star’s upper atmosphere. The particles scatter light near the blue end of the spectrum. What’s left for us to view is the red component of the star’s light.

As the particles build up, the star fades in brightness and also gets redder. Eventually, the carbon absorbs enough radiation to escape the star, and the cycle starts again.

To find La Superba, look a bit more than 7° north-northwest of magnitude 2.9 Cor Caroli (Alpha [α] Canum Venaticorum) in the constellation Canes Venatici. A sky-distance of 7° equals the field of view of many binoculars. And although you can find La Superba through binoculars, its color appears best through small telescopes.

Don’t forget this cluster
This week’s small telescope target is globular cluster M80 in the constellation Scorpius. It’s easy to find. First, locate the 1st-magnitude luminary Antares (Alpha [α] Scorpii). Then, move 4.5° northwest. M80 sits midway between Antares and magnitude 2.6 Graffias (Beta [β] Scorpii).

Charles Messier discovered this object in January 1781. He later added it to his catalog as number 80.

At magnitude 7.3, you’ll easily sweep up this globular through a 3-inch telescope. Its stars appear tightly packed, so a small scope won’t let you resolve the ones near M80’s bright core.

When you observe this cluster, you’ll notice the magnitude 8.5 star SAO 184288. It sits only 4' to the northeast of M80’s center. That star sits much closer to us than M80 and has nothing to do with the cluster.

A crowded field of galaxies
This week’s large telescope target is the Coma Galaxy Cluster, also designated Abell 1656, which lies in the constellation Coma Berenices. For those of you using go-to drives, “Abell 1656” may not be in your database. Instead, target either of this cluster’s brightest galaxies, magnitude 11.9 NGC 4874 or magnitude 11.5 NGC 4889.

Abell 1656 spans a whopping 4°. Within that neighborhood, hundreds of member galaxies lie in range of a large amateur telescope. The Coma Galaxy Cluster’s richest region, however, is the center, which measures 0.5° across and covers the same area as the Full Moon.

Even through a large scope, you won’t pull out much detail from individual members. The exceptions are magnitude 12.8 NGC 4911 and magnitude 12.5 NGC 4921. Both are spirals and respond well to magnification above 300x.

But, perhaps the main point of viewing the Coma Galaxy Cluster is just to see it. After all, this is a group of nearly 1,000 galaxies that lies more than 300 million light-years away.

--End transcript--

Previous podcast: Star V Hydrae, globular cluster NGC 5634, and the Ursa Minor Dwarf

February 27-March 6, 2009: constellation Columba, globular cluster NGC 1851, and spiral galaxy NGC 1808

Michael Bakich — Thu, 26 Feb 2009 20:46:00 GMT

Here is the transcript for my podcast about how to see constellation Columba, globular cluster NGC 1851, and spiral galaxy NGC 1808 this week.

Check out the Astronomy.com's interactive star chart to see an accurate map of your sky. It'll help you locate some of this week's key targets. Astronomy magazine subscribers have access to a slew of cool functions with StarDome PLUS.

Each week, I highlight three different night-sky targets for you to see:

One object you can find with your naked eyes or through binoculars
One object to find with a small telescope
One deep-sky object to find with an 8-inch or larger telescope for you avid astronomers

--Start transcript--

Biblical astronomy
This week’s naked-eye object is the constellation Columba the Dove. Specifically, it represents the dove that Noah sent out to test whether the waters from the great biblical flood had receded. It’s the only surviving constellation named after an object in the Bible. Columba first appeared in 1592, on a celestial map designed by Dutch astronomer and cartographer Petrus Plancius.

Columba is a constellation most amateur astronomers haven’t identified. Well, here’s your chance. Find Orion. That’s easy enough. Now look south of Orion, and find Lepus. I showed you how to locate this constellation 5 weeks ago. Finally, continue south from Lepus, and you’ll end up in Columba.

You’ll first notice the constellation’s two brightest stars. Phact (Alpha [α] Columbae) shines at magnitude 2.6, and Wasn (Beta [β] Columbae) isn’t far behind at magnitude 3.1. From there, use a star chart to find just three other stars brighter than 4th magnitude. Then all you have to do is make a dove out of those stars. Good luck.

When you look at Columba, you might want to wave goodbye. This constellation contains the point in the sky away from which our solar system is heading, relative to stars in our neighborhood. Astronomers call this point the solar antapex.

For those of you with large telescopes, there’s something at the approximate coordinates of the solar antapex. It’s the magnitude 13.2 galaxy IC 2153. Warning: Unless you can set up a large telescope at a dark site, you won’t have much luck observing this small faint object.

Alone in the dark
This week’s small telescope target is globular cluster NGC 1851 in Columba. It sits nearly 8° southwest of Phact, but you’ll see it easily from a dark site through binoculars. This magnitude 7.0 globular is the brightest deep-sky object for more than 20° in any direction.

Through a 4-inch telescope, you’ll see a concentrated core that you can’t resolve surrounded by many stars you can.

NGC 1851’s core is difficult to resolve through large telescopes as well because of its distance. It lies 40,000 light-years from the Sun and 55,000 light-years from the Milky Way’s center.

Bright, but few details
This week’s deep-sky object completes my trio of “Columba” objects. It’s spiral galaxy NGC 1808. This galaxy shines relatively brightly at magnitude 9.9.

NGC 1808 is easy to see and accepts high magnifications well because it has a high surface brightness. The galaxy’s oval shape — twice as long as it is wide — is apparent, but you’ll only see the initial stubs of the faint spiral arms that long-exposure images show stretching around NGC 1808’s entire length.

Through a 16-inch or larger telescope, crank up the power, and try to see the dark lanes near the galaxy’s outer edge. Astronomers recently discovered this galaxy has a high amount of star-formation occurring within it.

For those of you with the largest amateur scopes, three challenging galaxies lie roughly 10' southeast of NGC 1808. The brightest, PGC 620467, glows weakly at magnitude 15.6. The other two, PGC 131395 and PGC 16804, are really faint. Both of these galaxies have magnitudes of 15.9.

---End transcript--

Previous episode: Beehive Cluster, open cluster M50, and the Rosette Nebula
Previous transcript

February 13-20, 2009: Open cluster M41, the Tau Canis Majoris Cluster, and Thor’s Helmet

Michael Bakich — Thu, 12 Feb 2009 19:45:00 GMT

Here is the transcript for my podcast about how to see open cluster M41, the Tau Canis Majoris Cluster, and Thor’s Helmet this week.

Each week, I highlight three different night-sky targets for you to see:

One object you can find with your naked eyes or through binoculars
One object to find with a small telescope
One deep-sky object to find with an 8-inch or larger telescope for you avid astronomers

--Start transcript--

Follow the brilliant guide
This week’s naked-eye object is open cluster M41, which lies in Canis Major the Great Dog. It’s easy to find M41 on any clear winter night. First, find Sirius (Alpha [α] Canis Majoris), the night sky’s brightest star. Then look 4° due south.

Because it glows at magnitude 4.5, most observers should be able to pick out M41 easily with their naked eyes under a dark sky. This cluster lies 2,000 light-years away and measures about 20 light-years across.

Now just because you can see M41 without optical aid doesn’t mean you shouldn’t point your binoculars or telescope at it. Even a low-power view reveals dozens of stars with a 7th-magnitude orange gem at the cluster’s center.

Train your telescope on Tau
This week’s small telescope target is the Tau (τ) Canis Majoris Cluster, also known as NGC 2362. From M41, move 8.6° east-southeast. With unaided eyes, you’ll notice a glow around the 4th-magnitude star Tau CMa. When you point your telescope at this object, however, you’ll have a whole new perspective.

Tau CMa forms the centerpiece of this terrific star cluster. A 4-inch scope will show stars in three tiers of brightness. First, there’s brilliant Tau. Then, 3 magnitudes fainter, a half-dozen other stars catch your gaze. Finally, you’ll spot the faintest stars, which glow at 10th magnitude. Look closely for the tight group of these stars spanning 6' that surrounds Tau. Don’t let the brilliance of the principal luminary deter you.

For Asgard!
This week’s deep-sky object is my choice for “best-named” celestial target — Thor’s Helmet. Some historical illustrations (and the entire 600-issue run of the Marvel Comics’ superhero epic) picture the Norse thunder god Thor wearing a winged helmet. Well, through a large scope, this nebula, also known as NGC 2359, looks like a helmet with wings.

Thor’s Helmet completes this week’s trio of objects that lie in Canis Major. It sits 8.8° east-northeast of Sirius. This celestial treat is a cosmic bubble sculpted by radiation from a type of luminous, massive star called a Wolf-Rayet star.

Editor's note: Al Kelly submitted the image of Thor's Helmet above to Astronomy.com's Online Reader Gallery.

French astronomers Charles Joseph Étienne Wolf and Georges Antoine Pons Rayet discovered this stellar type spectroscopically in 1867. These short-lived supergiant stars are rare; astronomers have discovered fewer than 250 of them within the Milky Way.

To enhance NGC 2359’s visual appearance, use a nebula filter such as an OIII. Through a 12-inch telescope, you’ll see the circular central area and the helmet’s two “wings.” The brightest part measures 1' wide and extends to the south approximately 4'.

Recently, I observed Thor’s Helmet through a 30-inch telescope. The intricate details I thought visible only in photographs amazed me. If you have the opportunity to observe NGC 2359 through a large scope, take it. You won’t be disappointed.

--End transcript--

Previous episode: Canis Minor, M78, and the Witch Head Nebula
Previous transcript