Starwatch: When scope is set properly, look for the Perseus double cluster

Published 2:31 pm Thursday, January 15, 2009

I know that many of you got a new telescope under the Christmas tree, and I hope you’re having a lot of fun with it.

If this is your first telescope, let me give you some helpful hints. First and foremost, no matter how chilly it is, you have to set up your telescope outside.

Aiming it through a window, even an open window, is never a good idea. The warm air currents from your house will really mess up your scope’s ability to give you a clear view.

Another very important rule is to let it sit outside so the lenses and/or mirrors can acclimate to the cooler temperatures. Let your scope and all of the eyepieces you plan to use sit outside for a good half-hour. This really makes a difference.

One more important bit of advice is to use your widest aperture, lowest-power eyepiece when you’re first aiming at any telescope target. It’s much easier to find the object you’re looking for when you use a low-power eyepiece, because it offers you a wider field of view.

Once you get the target in view, you can use higher magnification eyepieces to really get a good look. Remember, though, that with any telescope, the higher magnification views will always be a little fuzzier than the low-power views.

There’s a whole universe out there to gaze at. Of course there are the moon and the planets. There’s also the wonderful Orion Nebula just below and to the right of the three famous belt stars of Orion, and there’s the Pleiades star cluster in the high southeastern evening sky here in Everett.

But if you really want to get your winter socks knocked off, check out the Perseus double cluster. I guarantee it will take your breath away when you first see it through your scope.

The Perseus double cluster is within the boundaries of the constellation Perseus. I think the best way to find the Perseus double cluster is to use the much brighter constellation Cassiopeia, the one that looks like a giant “W” in the sky.

In the early evening, directly face the eastern horizon and go straight up to the overhead zenith. You’ll see the “W” of Cassiopeia on its side a little to the left of the zenith.

Scan your telescope with a low-power eyepiece about 7 degrees, or less than the width of your fist at arm’s length, just to the lower right of the constellation. You shouldn’t have trouble finding the double cluster.

In fact, if you’re lucky enough to be looking for it in the dark country skies, you might even see it with the naked eye as a misty patch of light within the Milky Way band.

You can see two distinct open clusters, with some of the stars having reddish, sapphire blue and topaz tinges to them.

Not only is it wonderful eye candy through the telescope, but the Perseus double cluster is astronomically amazing as well.

Both of these side-by-side open clusters are large families of about 300 young stars each, not much more than 3 million to 5 million years old, all formed together in the same gigantic cloud of hydrogen gas and dust. Some of these stars are more than 50,000 times as powerful as our sun.

Both of these clusters are about 7,000 light-years away. (One light-year equals nearly 6 trillion miles.) We’re seeing them as they looked in about 5,000 B.C.

The much brighter Pleiades star cluster, not all that far away in the high southeastern sky, is only about 410 light-years away. If you could magically move the Perseus double cluster so it’s as close to us as the Pleiades cluster, the double cluster would fill more than a quarter of the northern sky and many of its stars would be the brightest stars in the night sky.

Also this week, if you’re an early riser like I am, you can catch the waning crescent moon in the low southeastern sky. On Wednesday morning, the moon and the bright reddish star Antares will be practically touching in the predawn sky.

Antares will be only half of a degree to the upper left of the crescent moon. Physically, though, Antares is about 604 light-years farther away than the moon on Wednesday morning.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the book, “Washington Starwatch,” available at bookstores and at his Web site, www.lynchandthestars.com.

The Everett Astronomical Society welcomes new members and puts on public star parties. The Web site is members.tripod.com/everett_astronomy.