Archive for June, 2009

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.

M51: The Whirlpool Galaxy

Friday, June 12th, 2009

0007m51
If you have dark skies and a good telescope, a real telescopic treasure is waiting overhead on these summer nights. The Whirlpool Galaxy (aka M51) is one of the finest spiral galaxies the backyard astronomer can see.  As can be seen from the picture, M51 has a clear central bulge and pair of spiral arms. And as a bonus, M51 comes with a small companion galaxy, NGC 5195. These features combine to give an awe-inspiring view with a ten or more inch telescope well away from city lights at about 150x magnification. But what if you have a smaller telescope and some light pollution to deal with? M51 should still be visible at lower magnification, but you’ll most likely just see two side by side fuzzballs – the cores of the two galaxies. Still, for something 27 million light years away, that’s a pretty good view in it’s own right.

 
0008m51map
Although technically in Canes Venatici, M51 can be easily found with a short star hop from Alkaid, the star at the end of the Big Dipper’s handle. It’s located almost halfway between 5th and 6th magnitude stars located slightly above (or below, depending on your point of view) Alkaid. Even if you don’t have the equipment and location to see all it’s detail, M51 is a telecopic treasure worth finding.

A Bucket Full of Photons

Monday, June 8th, 2009

As we all know, there are countless wonders to see in the night sky. But there remains the question of the best way to see them. In my opinion the answer to that question is a plain old “light bucket” – a common nickname for a Dobsonian mounted reflector. In real estate the mantra may be “location location location”, but with telescopes it is “aperture aperture aperture.” The bigger the aperture, the better. It’s all about how much light you can gather, and a “light bucket” just scoops it up. No other kind of telescope comes close to giving as much aperture for the cost as a Dobsonian. There are a couple downsides however. Large reflectors can be bulky and difficult to move around, and the Dobsonian mount isn’t suitable for astrophotography. But if you want great views without breaking the bank, they can’t be beat.

One great example is the Orion SkyQuest XT8 Classic Dobsonian Telescope. At only $329.95 it’s a great step up from many of the cheap starter scopes. Click the picture for more information on the XT8.

Orion SkyQuest XT8 Classic Dobsonian Telescope

Alberio

Sunday, June 7th, 2009

Many interesting things can be seen through a small telescope, but some are also beautiful. One of my favorites is the double star Alberio. To the naked eye, Alberio looks like a single star at the end of the constellation Cygnus (outlined in red) within the “summer triangle” (outlined in blue.) However even a small telescope can easily resolve it into a double star consisting of Alberio A (yellow colored) and Alberio B (blue-green colored.) This dramatic color contrast contributes greatly to it’s beauty. And it is that beauty, combined with the ease with which it can be found, and the fact it can be seen through any small telescope that makes Alberio an ideal target for beginning stargazers.

Cygnus and the summer triangle

Officially known as Beta Cygni, Alberio is approximately 380 light years from Earth. It is unknown whether Alberio is a true binary system or just two stars in the same area. However in 1976 Alberio A was itself discovered to be a binary star. Unfortunately, resolving Alberio A is well beyond the abilities of the typical backyard telescope.