Before you figure out which telescope to buy, you should spend a little time documenting yourself to get a better idea of what they are able to do, and to better discover your own needs.
The choice of astronomy telescopes depends upon the time you will devote to the observation, which site you have access to, the ease of use and control and, as often, your budget. Some positive aspects and drawbacks for some different astronomy telescopes are discussed here depending upon their designs.1. A refracting astronomical telescopemakes use of two lenses. The lens in the front of the telescope, called the objective lens, produces an upside-down image of the object. The lens near the eye, called the eye lens, acts as an ordinary magnifying glass to magnify that upside-down image. Naturally, each of these two elements of the telescope could be made up of a number of lenses, to combat certain inherent limitations, or aberrations.
Standard-quality achromatic or apochromatic refractors have some benefit over other telescope designs. Firstly, refractors, by default, bear a entirely clear aperture. There is no central obstruction that leads light to be distributed from brighter to darker areas. So, the visitor can experience a better contrast in refractors. In these telescopes refractors often are adduced as the premier instruments for a planetary and double star observation.
Low maintenance is the second bonus of refractors as lenses do not need recoating like mirrors do. Additionally, the optical tube assembly of a refractor generally does not depend upon collimation. Lens is placed into the tube and usually does not get misaligned, unless it is dag up to some major trauma.
As the refractor is a closed-tube assembly, it may demand a extended amount of time to cool to ambient temperature. Presently used thin-walled aluminum tubes have decreased this period substantially, but cool-down time still should be accept into account.
2. Newtonian reflecting telescopes consists of two mirrors — a large primary mirror at the bottom of the tube and a small, flat secondary mirror near the top of the tube. Front- lights arrive into the tube, fall on the primary mirror, get reflected to the secondary mirror, and then it is reflected again into the eyepiece.
This reflecting telescope does not ached any chromatic aberration. Included mirrors bear only one optical surface, whereas an apochromatic lens has between four and eight causing it less expensive to develop.
Secondary mirror forms what is called a central obstruction which leads to unnatural distribution of light and loss of contrast in the image. In case to resolve this problem, a few manufacturers have prepared so- called planetary Newtonians, having smaller central obstructions (some as small as 16% of the aperture).
Key things to remember when buying a telescope:a. Know everything you can about telescopes including manufacturers’ ads, catalogs, and especially read telescope reviews with customer rating on a particular product. The Astronomy magazine will be a useful resource for both advertise and telescope reviews.
b. If a telescope is included with low- quality, high- power eyepiece, high (albeit empty) magnifications can be attained. So, it is meaningless to claim 500x magnification for telescopes. To make change of the magnification of a telescope, you need to exchange the eyepiece.
c. If you are serious about buying a telescope, consult with your nearest astronomy club where you can get all the assistance on understanding all feature of a particular.
d. General review says that the bigger the telescope, the better to get view. But, if you need often use of it, then choose smaller one as it is easy to set up a small refractor on a basic tripod rather than a large Newtonian reflector on a heavy mount.
And finally, always remember: a telescope is a useful tool- but only if you know what to do with it !