Look up

by Phil Houseal as published in the Kerrville TX Community Journal Feb 25, 2009


For Jim McMahon, things are always looking up.

It's not just because he is an optimist, but because his hobby is astronomy.

The retired mathematician teaches Backyard Astronomy for Club Ed. His objective is to bring the mystery and wonder of the universe to your own backyard.

A curious mind helps, as does a pair of binoculars.

"A pair 7 x 35 binoculars - which a lot of people already have - comes in very handy," McMahon said. "If you can hold binoculars steady, you can see the satellites of Jupiter."

The first number is the degree of magnification, and the second number is the width of the lens in millimeters. So a set of field glasses 10 x 75 means they magnify the image 10 times and the lens is 75 millimeters across.

Is bigger better?

"Yes, because you can collect more light and see fainter objects," he said.

Higher magnification also means it is more difficult to hold the binoculars steady. So this is where serious astronomy buffs move up to reflector telescopes. They offer more magnification, more stability, and more features.

"This is an 8-inche telescope," McMahon said, pointing to his compact red viewer that he uses in class. "That means you can see very faint objects with this telescope."

Technically, his is a catadioptric telescope, which means the light is funneled through a series of lenses and mirrors before it reaches the eye.

"It folds the optics so don't have telescope too long and unwieldy," he explained. This allows for the performance of a large aperture and long focal length in a package that is lightweight and transportable.

You can go up quickly in sophistication by adding tracking devices, computer controls, and photography accessories.

Still, looking up at the night sky is an affordable and accessible hobby. Of course the best viewing is from an area far from the lights of the city. If you can't escape to the country, you can still get decent viewing if you shade the light. Put your scope in a tree's shadow, for example, to block out the mercury vapor street lamps.

When you observe the stars, you will be sharing an activity practiced by man from the first night he lay on his back. For ancient civilizations, the starry sky was the tableau for its bedtime stories, legends, and lore. Early astronomers learned to predict the seasons and track the passing of time. It still sparks the imagination of every person who takes the time to look up.

With McMahon's help, that appreciation of the skies can start outside your back door.

XXX


Backyard Astronomy begins Thursday evening, Feb 26. For information or to sign up, click www.clubed.net, or call 830-895-4386.

Club Ed is the Community Education program of the Kerrville Independent School District. Each year, we offer more than 400 classes throughout the Texas Hill Country, along with online courses, business and individual training, and after-school and summer camps. Comment online at clubedcomments.blogspot.com.