Articles About The Science Of Astronomy
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The invention of the telescope revolutionized the science of astronomy. Stars were now determined to be individual suns, and some stars were discovered in reality to be clusters of stars. Moons were discovered around the planets and ultimately more planets were discovered. There were only five planets known to the ancients - Mercury, Venus, Mars, Jupiter, and Saturn. The first scientists using their small telescopes to gaze upon the heavens were amazed by the new sights to greet their eyes.

Before the telescope could be invented the lens had to be discovered. It is unknown who made the first one. Possibly it was discovered by a glass maker as he crafted leaded windows, some of which require glass discs. A disc which was slightly concave would create a lens and if the glassmaker accidentally looks through it he might notice improved vision. In any case, lenses were in use for eyeglasses by 1300. A type of lens was known before this as the Greeks and Romans used water filled globes as burning glasses to start fires. Solid glass lenses were unknown until the thirteenth century.

The lens is described as a clear object consisting of plastic or glass or similar hard, clear material. It can be concave, convex, or plane shaped. The lens bends, or refracts light waves. It is used in telescopes, eyeglasses, microscopes, cameras and many more optical devices. Manufacture of the lens in modern times is not notably different than the methods used in the Middle Ages when they were invented except for Isaac Newton’s development of the use of pitch for polishing the lens surface.

The telescope took another 300 years to transpire and again was probably accidentally discovered. Who invented the telescope? That question is actually open to question! Many stories are in existence about the invention of this device. The best documented case is the tale of Hans Lippershey, a Dutch spectacle maker around 1600 AD. Children drifted into his shop and were playing with the lenses and happened to notice that certain lenses used in combination made distant objects seem closer. They informed Lippershey of this, he confirmed it, and began making telescopes. Other spectacle makers also made claims at about this same time, but Lippershey’s story seems the most likely and he may be the true telescope inventor.

At any rate, Galileo came into contact with the telescope around 1609. He began using the instrument and this turned his notion of the universe on its head. He was the first to see mountains on the lunar surface, Jupiter’s moons, sunspots, and the phases of Venus. He also was the first to conclude that the moon borrows its luminescence from the sun by reflecting its light and that the Milky Way consists of multitudes of stars. The use of the telescope also convinced him of the correctness of the Copernican sun centered solar system, for which belief he got into a great deal of trouble.

There are two types of optical telescope - reflecting and refracting. Reflecting telescopes make use of a lens/mirror system to magnify light. These typically can be made much larger than refracting telescopes can see dimmer objects, and the object viewed is seen with less distortion. Refracting telescopes use multiple lens systems to magnify. They are usually less expensive, are more portable, and are better for terrestrial viewing. The reflecting type is usually better for astronomical work. Galileo and others of his time used small refractors which probably had a magnifying power of about 30 times.

Two types of mounting systems are used - the altizimuth and the equatorial. The equatorial mounting system is usually more expensive, but much easier to keep on track of an object in the sky because only one adjustment must be made. The altizimuth is much cheaper, but requires more skill to track an object because two adjustments must be made to compensate for the earth’s rotation while viewing an object in the sky.

Generally for the amateur a high power telescope is not a good purchase. Since the magnification of light also tends to magnify the earth’s rotational speed in relation to the object being viewed, higher magnifications usually make heavenly bodies hard to track because of the increase of their apparent speed across the sky. On all by very clear nights, the extra magnification also magnifies the humidity in the atmosphere, creating distorted images. Light pollution from nearby lights will also be magnified making viewing difficult.

A lower power telescope will allow the casual sky watcher to still see a lot of things. The moons of Jupiter are readily visible with a low power telescope. Much detail on the moon’s surface is visible as are the rings of Saturn. "Stars" which appear as single entities to the naked eye will reveal themselves as star clusters with even a modest telescope. And the phases of Venus, similar to the phases of the moon, are also discernable with a small scope. The Milky Way, our galaxy, is resplendent with stars, clusters, and other beautiful sights, again all visible with a small telesscope.

It is usually best to purchase a small, multipurpose refractor to start with. One with a tripod is best. This will allow some modest astronomical observations and also use as a terrestrial scope. As interest in astronomy grows, a better, more expensive reflector scope with equatorial mount and computer tracking system may be purchased.
Amateur Astronomy Equipment