Backyard Astronomy , Your Crystal Ball Into the Past - by Ron Berry

First posted on 03-19-2008

What child has not looked up into the night sky and marveled at the sight? Those tiny specks of light painted against the infinite background of space have inspired poets to rhyme, composers to pen classics, scientists and philosophers to ponder our very origins.

Astronomy continues to be one of the more popular hobbies. One of the major reasons is that you can stargaze just about anywhere. Although country settings away from city lights are best, everyone can see the moon. Even though the closest star outside our solar system, Alpha Centauri, is over four light years away, you can see it easily with the naked eye.

While simple stargazing with the naked eye is great fun, using a telescope can be awe-inspiring. The view of the heavens through even a small telescope is something that you must experience in order to appreciate it. Even though modern technology allows us to view the celestial realm with images on TV and through the Internet, there is nothing quite like seeing it through a telescope.

Different Telescopes

There three basic kinds of telescope: the refractor, the reflector, and catadioptric.

1. The refractor telescope collects and bends light with a convex lens and eyepiece. This bending or refracting concentrates the light rays to a small focal point, making things appear larger or brighter.

2. The reflector telescope, as its name suggests, reflects light from a convex mirror in the back of the telescope to another mirror in the front and finally to the eyepiece. The convex shape of the mirrors ‘scoops up’ and concentrates the light to a focal point, thereby magnifying an object. Caution: Objects in a telescope appear closer than they really are!

3. The third type, called catadioptric, combines features from both reflecting and refracting telescopes.

Which One is Best?

For image quality and portability, my choice is the catadioptric. You can transport it easily, and it has the best features of both the reflector and refractor telescopes. Because of the design, catadioptric telescopes are almost completely free of the coma found in reflectors and the chromatic aberration in refractors. Chromatic aberration is the distortion of color due to a lenses inability to bring various colors in the light into focus. Coma is the distortion of an object at the edge of your field of view.

Convenience is another factor to consider. If you have to transport your telescope as I do, you will appreciate the catadioptric’s compact size, light weight, and ease of set up and take down.

Travel through Time

Light travels at an unimaginable speed of 186,000 miles per second. Even our sun’s light takes about 8 minutes to reach us. Now think about our closest neighbor, Alpha Centauri. It is over four light years away, so the light from its surface began its journey over four years ago. We are actually seeing it as it was more than four years in the past. In a sense, we are looking back in time.

Think back to what you were doing four years ago. Whatever it was, while you were doing it, light emanated from the surface of Alpha Centauri and came screaming along at 186,000 miles per second on the long journey toward earth, arriving here just a few minutes ago. Alpha Centauri is actually part of a star system of three separate stars; Alpha Centauri A and B form a binary, while Alpha Centauri C is 13,000 Astronomical Units (AU) away. This is part of the reason you can see it easily with the naked eye. You are actually looking at three stars instead of one.

Closer to Home

One need not look outside our own solar system to find amazing sites in the night sky. The moon may look smooth when seen with the naked eye, but train a telescope on it and prepare to be wowed. The level of detail will depend on your telescope, but the craters and jagged mountains are clearly visible. The best viewing, in my opinion, is when the moon is in a crescent stage, as the shadow created by the earth allows you to see much more detail.

I saw the moon for the first time through a telescope years ago. I watched as it slowly drifted past my field of view and could almost feel its movement. I knew it moved along its orbit around the earth, but to see it actually moving was an incredible experience.

Saturn, probably the most fun to observe because of the rings, makes for spectacular stargazing. Depending on the time of year, the rings of Saturn are visible and to this observer, quite breathtaking. While I cannot discern any colors or variations in the rings, they appear quite distinct from the planet itself, something I had seen only in books prior to viewing Saturn through a telescope.

Stand on the shores of any ocean and get a sense of the sheer enormity of it. Then realize it is not even a drop in a bucket by comparison to the size of the sky beneath which it sits. Looking up at the stars at night makes you realize just how massive everything really is. There is no number that can truly measure or even estimate its size or dimensions. The only thing that can even remotely compare to the wonder of space is the imagination of those who view it.

About the Author: Ron Berry is a freelance journalist who writes for Essay Street - and operates ScopeDoggie.com - the universal choice for telescopes online.