Guide To Astronomy Optics

Introduction Astronomy is a fascinating lifetime hobby enjoyed by young and old. Today, computerized telescopes and their accessories make it easy and exciting for beginners to find celestial objects and to track them as the Earth rotates.

What You Can See With A Telescope?

	THE MOON -- Our moon reveals a wealth of detail through even the smallest telescope. Its surface is rich with mountain ranges, impact craters, ejecta blankets and long, winding rilles. The moon's continually changing appearance will delight you as it goes through its phases. And occasionally you will be treated to a lunar eclipse.
	THE SUN -- Through safe, reliable filters, our sun is fascinating to study. Even an ordinary white-light filter will reveal sunspots, surface granulation, calcium clouds, solar limb darkening, and the 25-day solar rotation period. A hydrogen-alpha filter will reveal solar prominences. If you travel, then you may experience an awe-inspiring solar eclipse.
	THE PLANETS -- A high-quality 4" telescope will reveal Jupiter's cloud bands and its four Galilean moons that change positions hourly. Saturn and its splendid rings may be seen clearly and sharply, and Venus and Mercury may be watched as they pass through their moon-like phases. Observe Mars and see its polar cap change in size or watch its dust storms and its deserts change colors mysteriously with the seasons.
	STAR CLUSTERS -- Two types of star clusters are in the sky for you to discover. Open star clusters are loosely-arranged groups of a few dozen to hundreds stars. Globular clusters are tightly-packed aggregates of hundreds of thousands of stars.
	NEBULAE -- These glowing clouds of gas can be vast, irregularly-shaped clouds of gas and dust that are regions of star formation or small ball-shaped clouds of expanding gases from extinct stars.
	GALAXIES -- Remote "island universes," galaxies are composed of many billions of stars and exist in a variety of sizes and shapes reflecting their evolutionary history.
	COMETS -- Bright comets sometimes appear and can be spectacular as seen through rich-field telescopes.
	BINARY STARS -- Two stars closely orbiting a common center of gravity can be of strikingly contrasting colors for your viewing enjoyment.

What Are The Tools Of Astronomy?

	TELESCOPES -- The most important attribute of a telescope is aperture. Two other highly important attributes are optical quality and steadiness of mount. Most telescopes can be used for terrestrial viewing. You can also take pictures through your telescope since it can be used as a long-focus telephoto lens.
	ASTROPHOTOGRAPHY -- Astrophotography can be a rewarding experience. With the proper equipment, there is no end to the enjoyment of permanently recording your favorite celestial objects.
	CCD IMAGING -- The last few years have brought to the amateur astronomer an assortment of CCD (Charge Coupled Device) cameras. This new electronic imaging technology opens up a whole new world of astrophotography for amateur astronomers who can now obtain images quickly and easily.

Space images courtesy of www.nasa.gov