Clearing up the myth about power (magnification).
It slices it dices it has 675 power!!!!
Over the years, magnification has been the most misleading specification printed on those glossy color boxes of many department store telescopes. Exaggerated claims of high power are almost always a sure sign of an inferior product. The real important specifications in no particular order are as follows:
Stability of the mount ... does not vibrate and moves smoothly
Size of aperture ... light gathering power
Quality of optics ... reflectivity and transmission of light
Ease of use ... point and look. The telescope needs a good finder and, in our opinion, especially for the beginner, it MUST have a reflex sighting device of some type. (see reflex sight in glossary)
Please understand, we are not saying that power is unimportant, but it should be one of the last criteria you consider.
The amount of power you can apply is dependent upon several factors such as:
Focal Length ... focal length is the distance that the light in the telescope travels from the objective lens or mirror to the point where that light reaches focus (the focal plane). To determine how much power a telescope can deliver with any eyepiece, simply divide the focal length of the telescope by the focal length of the eyepiece.
For example: If you have a telescope with a 1000mm focal length and a 20mm eyepiece, that eyepiece will deliver 50 power (1000/20). The same eyepiece in a 2000mm focal length telescope delivers 100 power (2000/20).
Focal Ratio ... telescopes are rated with an "f" number. As you look at the telescope market, the products are given specification like (6" f/5). This means the telescope has a 6" aperture and a focal ratio of 5. As with cameras, focal ratio simply represents the speed of the optics. The smaller the "f" number, the faster the optics. But how does this relate to magnification?
With any given eyepiece, fast focal ratios (f/3 to f/5) deliver lower power, wider fields of view and usually brighter images. Because of these brighter images and wider fields of views, fast focal ratios excel at deep sky observing and can deliver stunning wide-angle views. Conversely, slower focal ratios (f/6 and up) deliver higher power and increasingly narrower fields of views. Slow ratios excel at observing the moon, the planets and binary stars.
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