Archive for the ‘Star Clusters’ Category

Also in Lyra

Tuesday, May 24th, 2011

The bright star Vega is probably the most famous object in the summer constellation Lyra. The second best known object in Lyra, and a favorite of backyard astronomers, would be the Ring Nebula. But I always like a good globular cluster, and M56 is a third object in Lyra you shouldn’t overlook. At magnitude 8.3, it’s not the brightest cluster around. But under dark skies it still makes for very nice viewing.

There are several options for star-hopping to M56. The one I usually use is to follow a line of three stars, nearly parallel to the “bottom” two stars of Lyra, and to take a turn east at the third star in that line. But with the other stars in the area, there may be another path that works better for you.

M3

Tuesday, March 29th, 2011

As the seasons change (and it becomes possible to spend more time at the telescope without freezing too badly) our favorite spring constellations are now available for prime time viewing. Among these is the small constellation Canes Venatici, notable for containing several galaxies and M3, a very nice globular cluster.  With an apparant magnitude of 6.2, M3 is a little beyond what most can see with the naked eye. But with even a small telescope it comes nicely into view.

The easiest way to find M3 is to start with the very bright star Arcturus, in the neighboring constellation Boötes. From there imagine a line to Cor Caroli, at magnitude 2.9 the brightest star in Canes Venatici. M3 can be found along that line, just a bit to the Arcturus side of center. With no bright stars nearby to guide you, M3 can be a bit tricky to find. You may have to sweep your scope along that line several times before spotting it. But once you find it, this globular cluster is worth the effort.

M41

Wednesday, February 23rd, 2011

Sirius, the brightest star in the night sky, dominates the view to the south this time of year. It also leads us to the easily found open cluster M41. Containing about 100 stars, M41 (aka NGC2287) is roughly four degrees straight south of Sirius. It’s large dimensions, bright magnitude and easily found location make this cluster a great target for beginning astronomers.

Open Cluster M52

Thursday, September 2nd, 2010

As we move into autumn, the longer nights and still warm weather make this my favorite time of year for astronomy. It’s also a time of year that gives us a wide variety of celestial treats. One of these treats that is often overlooked is the open cluster M52 in Cassiopeia. While not the biggest or brightest cluster, the combination of M52 with brighter nearby stars creates a pleasant arrangement. It also has the benefit of being very easy to find. Simply follow the line formed by the two brightest stars in Cassiopeia for about the same distance as that between the two stars. Getting a good look at M52 will require a somewhat larger telescope, but it is well worth the effort – or it would be if there was all that much effort involved.

Coma Star Cluster

Friday, May 14th, 2010

When we think of astronomy, we usually think of peering through a telescope at some faint fuzzy out in deep space. But the good news for beginners who may not own a telescope is that some deep sky objects are best seen through a pair of binoculars (which really are just a pair of small telescopes anyway.) One such object is the Coma Star Cluster (officially known as Melotte 111) in Coma Berenices. At a distance of 288 light-years, this open cluster is close enough to cover more than five degrees of sky. With only about 40 stars, it’s not one of the more densely packed clusters. But the good news is that a dozen or so of the stars are bright enough to be seen even from light polluted areas.

Finding the Coma Star Cluster is easy as it lies almost halfway between two bright stars. Start with Denebola, the bright star at the “tail” of Leo, and look toward Cor Caroli. The Coma Star Cluster will be right in between. If you’re not sure which star is Cor Caroli, look toward the end of the Big Dipper’s handle when moving away from Denebola. Cor Caroli will be about two thirds of the way to Alkaid, the star at the end of the handle.

M5 in Serpens Caput

Monday, May 3rd, 2010

Globular clusters can be among the most beautiful objects in the night sky, and I rarely miss the chance to see one. Well situated for viewing this time of year is M5 in Serpens Caput. With a diameter of roughly 165 light-years, M5 is one of the larger known globular clusters. And at magnitude 5.8, it’s also bright enough to show some nice detail.

Bright Arcturus is a good starting spot for a star-hop to M5. Imagine a line to the southeast to delta Ophiuchus. A little to the side of that line will be alpha Serpens. At around magnitude 2.7, both of these stars are much dimmer than Arcturus,  but are still bright enough to be easily found. M5 can be found roughly across the line from alpha Serpens. It’s not one of  the more exact star-hops, but it doesn’t need to be. Once you’re in the area, M5 should show up nicely in your finder scope, giving you the chance to enjoy this bit of deep sky beauty.

Cancer’s Second Cluster

Thursday, February 25th, 2010
M67

Last time we took a look at M44, the Beehive Cluster, in Cancer. But M44 isn’t Cancer’s only cluster worth seeing. There is also M67, just a little to the south. At magnitude 6.9, it makes a very nice telescopic target. One difference between M67 and Cancer’s more famous cluster is that M67 is about six times as distant. With Mars still in the area and showing up nicely, this is still a very interesting part of the sky.

The Buzzing Little Bees of M44

Sunday, January 17th, 2010
M44 in Cancer

For the amateur astronomer, few things can match the beauty of a densely packed open cluster. One of my favorites has always been M44, the Beehive Cluster, in Cancer. With it’s brightest star at magnitude 4.2, Cancer is a rather dim constellation and not always obvious to the backyard astronomer, especially when light pollution is an issue. But as can be seen on the map, Cancer is located between the easily found constellations of Leo and Gemini. Also currently passing through that area is Mars. So don’t forget to crank up the magnification and see how much surface detail you can see on the red planet.

Despite being one of the closest star clusters, there is some disagreement about the exact distance to the Beehive Cluster. Current estimates range from about 520 to 610 light years. Being this close means it appears both large and bright (at magnitude 3.1, visible to the naked eye under dark sky conditions.) And so it is best seen with low magnification. A good pair of binoculars would work well, otherwise use the lowest power eyepiece you have.

M45

Sunday, November 15th, 2009
The Pleiades

It may be known to science as Messier 45, but throughout history the Pleiades has gone by many names, including the seven sisters and the Maia Nebula. Subaru is the Japanese name for the Pleiades. The Arabic name is al-Thurayya. The ancient Hebrews called it kimah, and it is mentioned in the Bible. It is also important in Hindu mythology, where it is known as Krittika. If I wanted to, I could go on for a while with this list of names, as nearly every ancient culture has it’s name for the Pleiades. But I think you get the idea; people have been looking at this star cluster for a long time. And now we’re getting to the time of year where you can too. The Pleiades are in the east, in the constellation Taurus, in the late evening. Clearly visible to the naked eye as a bright patch, a good pair of binoculars are the best way to enjoy the cluster as a whole. A telesope will probably have too much magnification to see the whole thing at one time. However a good telescope will let you see the nebulosity surrounding the hot blue stars found in the Pleiades.

One of the reasons the Pleiades is such an obvious and easily visible cluster is because, at 440 light years, it is also one of the closest open star clusters to Earth. This makes it a little odd it was ever included in Charles Messier’s famous catalogue. Back in Messier’s day, finding a comet was the way to become famous as an astronomer. And so Messier catalogued objects that could be mistaken for comets. But it seems very unlikely someone would make that mistake with such a well known star cluster. In any event, if you’re trying to see how many Messier objects you can spot, this is about the easiest one out there.

Three Clusters in Auriga

Friday, October 23rd, 2009

Why look at one star cluster when you can see three of them? In the constellation Auriga, now showing up in the East around midnight, three moderately bright, but densely packed open clusters line up very nicely. The stars of Auriga are quite bright, so the pattern of the constellation should be easily visible. In the right side of that pattern, a line of stars (circled in yellow on the map) is faintly visible to the naked eye, and easy to spot through a finder scope. Follow the line of these stars to the left, and very quickly you’ll come to the first of these clusters, M38. Once you’ve found M38, start scanning down and you’ll find the other two clusters, first M36 and then M37. All three clusters are between magnitude 5.6 and 6.4 in brightness, with a large number of stars making each a telescopic treat.

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