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.

Lowest useful magnification is the power at which the exit pupil becomes 7mm in diameter. Powers below this can still be reached with the telescope to give wider fields of view, but the image no longer becomes brighter at a lower power. This is due to the fact that the exit pupil of the telescope (the beam of light exiting the eyepiece) is now larger than the average person's dark adapted pupil, and no more light can fit into the eye.

"Diffraction Limited" means that the limits of image detail are determined by the physical properties of light, and not by optical defects in the telescope.

A universal attachment system for holding the optical tube onto the tripod. A dovetail bar is attached to the tube rings, then it slides onto the mount itself, making for quick assembly and disassembly.

Some mounts are compatible with a motorized Go-To system for fully automated computer finding of objects in the night sky. Others mounts are compatible with computer finding systems which require the user to manually move the mount to the object's position as indicated by the computer finder.

The latitude range refers to the usable range on the EQ mount's latitude axis. If you live above or below the latitude specified, the mount may not be able to polar align properly because of interference with the counterweight shaft or the polar axis housing.

The height range specification is a measure of the tripod itself - not the eyepiece height. Since telescopes come in all shapes and sizes, the eyepiece height will vary, even when using the same tripod. For an EQ tripod the mount is set up so the counterweight shaft is horizontal, and then the height is measured from the ground to the center of the mounting plate.