Binoculars are two small telescopes, sealed into one package. The majority of binoculars use Galilean optics, or a convex objective and a concave eyepiece lens. Binoculars offer low light levels and small magnification, which can make it useful to amateur astronomers whom are just seeking a casual perusal of the sky. The large view field of binoculars is useful when watching large deep sky objects such as the Milky way, nebula and galaxies though one will likely be unable to view asteroids or moons.
Because telescopes and binoculars are similar in design, many of the companies which product telescopes already manufacture binoculars. In fact, several popular telescope companies gained their start by making binoculars for outdoors and sports optics. Binoculars are used in many areas of the world from the high class operas (opera glasses) to the military with their night-vision goggles and eye-wear fitted with laser beam filters.
The major difference between binoculars and telescopes is the binoculars' exit pupil and eye relief. The eye relief in a pair of binoculars is the distance from the rear eyepiece lens to where the image is formed while the exit pupil is where the objective lens gathers light and focuses into a beam. The most important consideration with binoculars is the optical coating. Since binoculars have 16 points on their surface where light is lost a lower quality product will have a blurred image. Lens coatings serve to help the light from getting lost in order to create a more crisp image for the viewer. There are four different levels of coatings to consider:
Be careful when looking at binoculars as any product which claims it has plastic lenses does not provide any coating.
Binoculars have two different types of focus abilities. One is referred to as independent and the other central. Independent means that each tube must be adjusted separately from the other. This type of focus is usually found on more heavy-duty binocular models. The latter type, central, means that both tubes are adjusted at the same time. This is the more common type. There are focus-free models, also referred to as fixed-focus, but these types of binoculars lack adaptability and the range of view is not as precise.
Do you have something to say about Binocular Astronomy? Be the first to comment using the space provided below.
Bookmark this page with:
Delicious
Digg
reddit
Facebook
StumbleUpon
More helpful advice in
The Forum
NASA lays out final flights of shuttle fleet
Science editor Alan Boyle's Weblog: NASA sets dates for the space shuttle fleet's final 10 missions,...
3 artists get creative aboard ‘vomit comet’
Three British artists tried Tuesday to make art in zero gravity aboard an aircraft used to train cos...
What makes Earth so special?
Understanding what's special about Earth is crucial for finding other planets out there and predicti...
Mars lander breaks new ground
NASA's Phoenix Mars Lander delivered a second sample of Martian dirt to its onboard wet chemistry la...