Archive for the ‘Nebulae’ Category

The Great Orion Nebula

Monday, January 31st, 2011

While looking over what I’ve written about the sights enjoyed by amateur astronomers, I noticed a glaring omission. Somehow I haven’t mentioned M42, the Great Orion Nebula, among the most observed objects in the night sky. This diffuse nebula is among the brighest, and is even visible to the naked eye. M42 is estimated to be 24 light years across and is at a distance of about 1350 light years. Besides being a favorite sight for amateur astronomers, scientists are also interested in M42 as a region of stellar formation. An interesting bit of trivia is that in 1880 the Orion nebula became the first target of deep-sky astrophotography.

Finding the Orion Nebula could hardly be easier. Simply look to the “sword” below Orion’s belt. If you have a larger telescope and dark skies, there are plenty of other nebulae and interesting features within this area of Orion. But large telescope or small, the Orion nebula is always an enjoyable target.

The Winter Crab

Monday, January 17th, 2011

Among the Messier Objects dotting the night sky, you will find numerous galaxies, planetary and diffuse nebulae, and open and globular star clusters. But M1, the Crab Nebula, is unique in being the only supernova remnant to make Messier’s list.  Created by a supernova observed by Chinese and Arab astronomers in 1054, the Crab Nebula itself was first observed in 1731.  Located at a distance of roughly 6500 light years, the nebula is expanding at a rate of 1500 km/s. This expansion was discovered in the early 20th century by comparing photographs of the nebula taken several years apart.

To see the Crab Nebula, you’ll need reasonably dark skies. At magnitude 8.4, it can be easily washed out by light pollution.  From my home on the edge of a mid-sized city, it’s just barely visible. But with dark enough skies, it makes a nice target for small telescopes. Located in the constellation Taurus, the easiest way to find the Crab Nebula is to start with the Hyades star cluster (the asterism known as the “head of the bull”). Follow the line formed by the “bottom” of the Hyades to find Zeta Taurii. Going up from there, the Crab Nebula can be easily found. Once the upcoming full moon gets out of the way, we’ll be moving into prime time to see this winter crab. (Does that make it a snow crab?)

The Summer Dumbbell

Sunday, July 12th, 2009
The Dumbbell Nebula

As summer continues, let’s turn our attention back to the “summer triangle.” There aren’t all that many planetary nebulae visible to the backyard astronomer, but one of the better ones can be found in the constellation Vulpecula. The Dumbbell Nebula (M27), discovered by Charles Messier in 1764, was the first planetary nebula discovered. It’s magnitude is a bright (by nebula standards) 7.5, and shows the interesting dumbbell shape that led to it’s name.

M27 in Vulpecula

Although M27 is in  Vulpecula, the easiest way to find it is to start with the constellation Sagitta. Using your finderscope, scan up from the end of Sagitta and look for an upside down bowl shape (outlined in yellow) with a star in the middle. Point your telecope at that star, and M27 will be right next to it. It’s easy and worth finding.

The Lagoon in the Teapot

Sunday, June 28th, 2009
M8: the Lagoon Nebula

As we move toward July, warm summer nights bring a wealth of new celestial treasures appearing in the southern skies. One of the finest is the Lagoon Nebula (M8) in the constellation Sagittarius, ofen known as the teapot constellation for it’s obvious central shape. One of only two star forming nebulae just barely visible to the naked eye from northern latitudes, it can be an awe inspiring sight through even a small telescope. An emission nebula roughly 4100 light years away, the Lagoon Nebula shows an amazing amount of detail. A cluster of stars dominates the eastern side of the nebula, while a belt of dusty material seems to divide it nearly in two. Under light polluted skies, only the brigher western side of the nebula may be visible. A nebula filter will help show the nebulosity more prominently, but will also dim the embedded stars.

Above the "Teapot"

M8 is an easy nebula to find. Look above the western side of the “teapot”, following a line through the stars at it’s upper left and top. With an apparent magnitude of 6.0, it should be easily visible, and well worth finding on a summer night.

M57: The Ring Nebula

Tuesday, May 19th, 2009
M57

The constellation Lyra, in one corner of the famed “summer triangle”, is home to Messier 57, commonly known as the Ring Nebula. A classic example of a planetary nebula, M57 is not one of the larger or brighter Messier objects. However it is easy to find and, even through a small telescope, lives up to it’s “ring” name. To find M57, start with Vega – a very bright magnitude 0 star at the westernmost corner of the summer triangle. Trailing off to the east of Vega, the shape of the constellation Lyra can be faintly seen. Aim your telescope with a low

Lyra

power eyepiece about halfway between the two stars at the “bottom” of Lyra. M57 should be visible as a small ring near the center of your field of view. Switching to higher magnification can allow a closer look at the ring structure. Despite a dim magnitude of 8.8, M57 is easily visible and shows a surprising amount of detail, making it a worthy telescopic target. As is common for planetary nebulae, the distance to M57 is difficult to determine. Estimates have ranged from 1000 to 5000 light years, with a current best estimate of around 2300 light years.