Archive for April, 2010

Arc to Arcturus

Saturday, April 24th, 2010

Every amateur astronomer (or at least those without GoTo scopes) understands the importance of being familiar with the constellations and bright stars of the night sky. These are the signposts that let us “star-hop” our way to faint fuzzies we’re trying to find. One of the most important signposts, high in the night sky at this time of year, is an orange giant star called Arcturus. With a visual magnitude of −0.05, Arcturs is the brightest star in the constellation Boötes and the third brightest star in the night sky.  Follow the arc of the Big Dipper’s handle toward the south, and bright Arcturus will be quickly found.  Continue following the same arc to the south and you’ll come to Spica, a blue giant, and the brightest star in the constellation Virgo.  This path gives rise to the old saying “Arc to Arcturus, then speed on to Spica.”  If you’re an experienced amateur astronomer, this path is well known.  If you’re just learning, or would like to learn, try to follow the arc tonight and learn two of the main signposts in the night sky.

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 April Lyrids

Tuesday, April 6th, 2010

After more than three months without a good meteor shower, the Lyrids will reach their peak on April 21 and 22. Although typically a slow shower with only about ten or so meteors per hour, the Lyrids will occasionally have brief outbursts of more than ten times that rate. Although the moon could interfere earlier in the night, it will be low in the west during the peak viewing hours closer to morning.

Mercury Evenings

Tuesday, April 6th, 2010

Low in the western horizon, just after sunset, is a nice pairing of planets. Easily visible is the always bright Venus. But just to it’s right is the usually more elusive planet Mercury. A bright magnitude -0.2, and being near the even brighter Venus, makes this an excellent opportunity to see our solar system’s innermost planet. At the same time, high in the south in the constellation Cancer, the planet Mars is visible. And in the southeast in the constellation Virgo, you can see Saturn. It’s not often you can see four out of the five naked eye planets at the same time. But if you have a clear view of both the east and west horizons the next few nights, you’ll get your chance.