Archive for the ‘Galaxies’ Category

One of the Pinwheels

Wednesday, April 14th, 2010

High in the northern sky, just a little above the handle of the “Big Dipper,”  is the grand spiral galaxy M101. As we can see it face-on, M101 is one of several galaxies sometimes called the “Pinwheel Galaxy.” M101 is a large galaxy, nearly twice the size of the Milky Way, and is estimated to be about 27 million light years away. Despite being so large and having a magnitude of 7.86, M101 appears quite diffuse and so isn’t an easy target for smaller telescopes. But if you have dark skies and a nice big Dob, this pinwheel is worth checking out.

The Triangulum Galaxy

Friday, December 4th, 2009

It’s getting to the time of year where a heavy coat and thermos of coffee are essential astronomy equipment. The last few days have really started feeling like winter in my part of the world. But if you brave the cold and venture out, the winter sky holds some real treats. One of them is the galaxy M33, the Triangulum Galaxy. There are times when, because of it’s appearance, M33 is called the Pinwheel Galaxy. However the name Pinwheel Galaxy officially refers to M101 – itself a worthy telescope target in the constellation Ursa Major. At magnitude 5.7, M33 can be seen with the naked eye if skies are sufficiently dark. Even under moderate light pollution, it makes a good telescopic target with a low power eyepiece. Being about 3 million light years away, M33 is part of the Local Group of Galaxies. It’s nearly face on view gives a great view of M33′s spiral structure. So heat up the coffee and take a look.

Finding M33 in Triangulum

Celestial Royalty

Sunday, August 16th, 2009

Named for the princess Andromeda in Greek mythology, the Andromeda galaxy (aka M31) is a bit of celestial royalty on late summer nights. Andromeda is a spiral galaxy similar in size to (or, depending on who you ask, a bit larger than) our own Milky Way. It is also the nearest spiral galaxy to the Milky Way. These two combine with the Triangulum Galaxy and about thirty smaller galaxies to form the Local Group. While telescopes have captured many stunning images of Andromeda (including the mosaic image found here), the smaller image on the right is more typical of what you can expext to see through a small telescope.

Finding Andromeda

Finding Andromeda shouldn’t be a challenge. Start with the easy to find constellation Cassiopiea, and imaginine a line to the right from it’s “bottom” two stars. (This is earlier in the night, when these constellations are moderately high in the east. And while it’s not a completely straight line, it’ll get you headed in the right direction.) Then look for the bright, magnitude 2 star in the constellation Andromeda, and go up from there. Tracking up from that star toward the line you imagined from Cassiopiea should lead you right to the galaxy. Although, if you have dark skies and keen eyes, all this star hopping may be unnecessary. With an apparent magnitude of 4.4, Andromeda is one of the brighter Messier objects and is visible as a faint smudge to the naked eye under good conditions. At a distance of roughly 2.5 million light years, it is one of the most distant objects visible to the naked eye. While Andromeda is easy to find, seeing how much detail you can resolve is a good test of your telescope’s abilities. Can you see more than a bright core surrounded by a gray smudge? And while looking at Andromeda, don’t miss it’s satellite galaxies; the ellipicals M32 and M110.

M51: The Whirlpool Galaxy

Friday, June 12th, 2009

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.

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.