Full-Sized Astronomy Binoculars
Although small, pocket-sized binoculars will help you magnify the moon or see constellations close to earth, the full effect of viewing the night sky is not brought out until you spend a little more on full-sized binoculars. The larger the pair of binoculars, the larger the aperture, and aperture is what determines the amount of magnification. Magnification refers to making objects bigger and using the available light to enhance viewing. A larger aperture allows more light to enter the viewing area. Prices for these binoculars can be as little as $50, with $115 being a good mid-range price.
Giant Astronomy Binoculars
Giant astronomy binoculars are aptly named. The lightest of these big binoculars weighs in at 4.4 pounds and needs to be mounted on a tripod for best use. Their large field of vision allows the viewer to take in more of the night sky, and the extra large aperture provides maximum magnification and optimal use of available light. Prices for these binoculars start at around $150 and reach into the thousands.
Porro Pism Binoculars
Porro prism binoculars use prisms to refract light and enhance the viewing image. The prisms also present the viewer with a properly oriented image. Without prisms the image would be presented upside down. The advantage of the Porro prism is that it allows for enhanced magnification in smaller binoculars. This type of prism also allows for more inexpensive binoculars. Porro prism binoculars have fallen out of favor recently, and many binocular manufacturers have ceased making them.
Roof Prism Binoculars
Roof prism binoculars are so named because the prism looks like a small roof. Older style binoculars using Porro prisms have a dog leg shape whereas roof prism binoculars have a more linear and straight shape. Alignment is crucial for these binoculars, so when you buy, purchase binoculars with a sturdy housing that securely holds the prisms in place. As with all binoculars, aperture size is the determining factor with roof prisms. The larger the aperture, the greater the viewing distance the binoculars will have.