HOW TO BEGIN OBSERVING

Many people buy a telescope too early.  If you do not own a telescope, do naked eye observing so you know your way around the sky.  Visit Observatories or join a Club, and take the advantage of looking through a variety of telescopes. Purchase a Planisphere (sky map)  to help you find objects.  Sky watching with the naked eye will make you familiar with the main constellations and accustom you to the changing sky. Learn key stars and constellations before buying binoculars or a telescope.

BINOCULARS

Binoculars will allow you to see the craters on the Moon, four moons of Jupiter, and five or ten times as many stars as can be seen with the naked eye. Dozens of asteroids come within reach of binoculars each year, while bright comets look spectacular.  Not bad for a piece of equipment costing only about a quarter of the price of a standard beginners telescope. Binoculars are essentially two low-powered telescopes joined together, so that you can look through them with both eyes instead of just one.

The performance of binoculars depends on the diameter of the objective lenses (the lenses at the front) as well as on the magnification that is provided by the eyepieces.  Various combinations of lens and eyepieces provide a considerable range of possibilities.  For night viewing, experience observers recommend using a pair of 7 x 50 binoculars, which always use the porro-prism design.  The 7 refers to the magnification and the 50 refers to the diameter of each of the objective lenses (millimeters). Binoculars with 80mm objective lenses are also commonly available, but a pair that large should have a mounting.  An ideal mount for binoculars is a sturdy camera tripod.

TELESCOPES

Size and stability should be your main considerations when buying a telescope.  As a rule of thumb, buy the telescope with the largest mirror or objective lens you can afford.  Usually a reflecting telescope will provide larger optics than a refractor of the same size.  The result is more light coming into your eye and brighter images of faint stars and galaxies.  

Refractors tend to give sharper, brighter images than reflectors of the same aperture because their optical elements are far less likely to slip out of alignment.  However, refractors of about 4 inch (100mm)aperture are physically far bigger than their reflecting cousins - an important consideration if you want to move your telescope around.

If you have a limited budget, you might initially opt for a reflector with a 4 inch (100mm) diameter mirror, whereas a more serious sky watcher might choose one of 8 inch (200mm) diameter or more.  Buying a good quality 2.4 or 3 inch (60 or 75mm) refractor might also be a wise choice for a beginner.