Beginner - Suited for a wide range of uses, Level 1 telescopes are simple to operate and set up. Some initial assembly may be required. Very good optical and mechanical quality. Great for families, young people, and folks who don't want to mess with equipment but just want to take a look. Any of these scopes will show you countless lunar craters, Saturn's rings and a myriad of star clusters and nebulas! Referring to the manual is recommended.

Intermediate - These scopes offer higher performance and more advanced features than Level 1 models. They typically take a bit longer to learn and need some set-up or adjustments. But anyone with the slightest technical bent will have no problem getting familiar with these models. Referring to the manual is recommended.

Advanced - These scopes provide the best performance but may require more skill to master and appreciate. They have exceptionally fine optics and mechanics. Some are easy to use but are but on the large or heavy side. Some are intended for specialized uses. These scopes will appeal to the more technically inclined. Referring to the manual is highly recommended.

Expert - Expert telescopes offer uncompromising optical and mechanical quality for the most demanding amateur astronomer. They may be technically involved or designed for specialized use, such as astrophotography or detailed deep sky observation. They carry a premium price, but are designed to provide the ultimate performance in the field. Referring to the manual is highly recommended.

The focal ratio of an optical system is the ratio of a telescope's focal length to its aperture. Short focal ratios (f/5, f/4.5) produce wide fields of view and small image scales, while long focal lengths produce narrower fields of views and larger image scales.

The theoretical resolving power of a telescope can be calculated with the following formula: Resolving power (in arc seconds) = 4.56 divided by aperture of telescope (in inches). In metric units, this is: Resolving power (in arc seconds) = 116 divided by aperture of telescope (in millimeters). Note that the formula is independent of the telescope type or model, and is based only upon the aperture of the telescope. So the larger the telescope's aperture, the more it is capable of resolving. This is important to keep in mind when observing astronomical objects which require high resolution for best viewing, such as planets and double stars. However, it is usually atmospheric seeing conditions (not the telescope) which limits the actual resolving power on a given night; rarely is resolution less than one arc-second possible from even the best viewing locations on Earth.

The astro-photographic capability of the telescope is based on the style, stability, and accuracy of the mount and tripod. Telescopes on either very lightweight mounts or non tracking mounts (such as Dobsonians) are capable of only very short exposures such as lunar photographs. If a motor drive is attached to an equatorial mount, even a small lightweight mount is capable of capturing some planetary detail. Larger EQ mounts that utilize very precise tracking and excellent stability are capable of longer exposure deep-sky photography.

A motor drive automatically moves the telescope in right ascension at the same rate as the east-west drift of the stars so stars can be continuously tracked in the eyepiece without manual adjustment. Motor drives are usually equipped with a hand control that allows the telescope's tracking speed to be slightly increased or decreased, which is particularly critical when taking long-exposure astro-images.