Share this article on Facebook Share this article on Twitter Share this article on Google+ Share this article on Linkedin Share this article on StumbleUpon Share this article on Delicious Share this article on best telescope for viewing planets Digg Share this article on Reddit Share this article on Pinterest Expert Author Kevin Manning
A telescope is a powerful tool used in exploring objects throughout the universe. They literally enable us to see the invisible! Telescopes are also a time machine, allowing us to peer into the past. The word telescope was derived from the roots tele, which means “distant,” and skopos, which means “to see.” So a telescope is an instrument that allows us to see distant objects, such as the Moon, planets, stars and star clusters, nebulae and remote galaxies. 2009 marked the 400th anniversary of the first telescope pointed to the night sky by the famous mathematician, scientist and astronomer Galileo Galilei. Modern telescopes are far superior in optical quality than these earlier instruments. Just like the pupil of our eye gets larger in the dark to let in more light, the larger the telescope’s optics the more faint light from distant stars and galaxies appear brighter, allowing us to see further and deeper into space. A second benefit with a larger telescope is its ability to resolve smaller and finer details on extended objects like the Moon and planets, and permit the clear separation of close double stars.
Perhaps you are interested in purchasing a new telescope. Basically, there are two types of telescopes to choose from. A refractor uses lenses to collect and bend light as a cone to a focus. Binoculars are merely two refractor telescopes mounted side by side. Reflectors use a set of mirrors to gather light, which is brought to a focus by virtue of a concave curve (inward like the scoop of a spoon) on the front surface of the primary (largest) mirror. Light enters a mostly hollow tube and reaches the primary mirror at the bottom. As the reflected cone of light (due to the curve) travels up the tube, it is intercepted by a smaller flat (plane) diagonal mirror set at a 45 degree angle with respect to the light path. 45 + 45 = 90 degrees, so the light is sent outside the tube at a right angle for the observer to inspect a focused image through an eyepiece (ocular). This is a classic Newtonian reflector, named after another famous scientist, Isaac Newton who created its design. The distance between the primary objective (lens or mirror) and the eyepiece where the focal point is reached is called focal length. This is determined by how steep or shallow the curve in the glass is. A greater curve will focus light in a short distance, so the telescope tube will be correspondingly shorter as well. A shallow curve will extend this distance,