All telescopes fall into one of three optical classes. The relative advantages of
each of these telescope designs will be made clear below.

In the refracting telescope
(a) light is collected by a 2-element objective lens and brought to a focus at F.
By contrast the reflecting telescope
(b) uses a concave mirror for this purpose. The mirror-lens, or catadioptric, telescope
(c) employes a combination of both mirrors and lenses, resulting in a shorter, more portable optical tube assembly.
All telescopes use an eyepiece (located behind the focal point, F) to magnify the image formed by the primary optical system

Refracting Telescopes use a large objective lens as their primary light-collecting element.
Meade refractors, in all models and apertures, include achromatic
(2-element) objective lenses, in order to reduce or virtually
eliminate the false color (chromatic aberration) that results in the telescopic
image when light passes through a lens.

Reflecting Telescopes use a concave primary mirror to collect
light and form an image. In the Newtonian type of reflector, light is reflected
by a small, flat secondary mirror to the side of the main tube for
observation of the image.

Mirror-Lens (Catadioptric) Telescopes employ both mirrors and lenses,
resulting in optical configurations that achieve remarkable image
quality and resolution, while housing the optics in extremely short,
highly portable optical tubes.

TELESCOPE MOUNTS

Once an object, whether terrestrial or astronomical, is located
and centered in the telescope's field of view, the telescope's
mechanical mounting permits the observer to track, or follow,
the object as it moves across the landscape or sky. Types of telescope
mountings include the following:

Altazimuth Mountings

The simplest type of telescope mount allows the telescope
to be moved up-and-down (in vertical, or altitude) and left-to-right
(in horizontal, or azimuth). The altitude-azimuth (altazimuth)
mounting thus permits the observer to follow objects by simple motions
of the telescope in vertical and horizontal. Slow-motion controls, sometimes
operated through flexible cables, can facilitate these motions. The altazimuth
mount, owing to its simplicity and relatively lower cost, is widely used with
telescopes in both land-viewing and astronomical applications.
Example: Meade Model 390.

The Meade Model 390 includes an
altazimuth mount, for horizontal and verticle tracking.

Equatorial Mountings

Although celestial objects are essentially fixed in their positions
in the sky (on the celestial sphere, the imaginary spherical surface on which
all astronomical objects are located), they appear to move in an arc across the
sky, as the earth rotates underneath the sky once every 24 hours. From an
astronomical point of view, therefore, the task of the telescope mounting is
to compensate for the Earth's rotation and allow the observer to track the
Moon, planets, and stars. This task is made vastly easier by the equatorial
mounting, the type of mounting incorporated into most larger or more
advanced telescopes. By aligning one axis of the equatorial mount to the Earth's
rotational axis (a simple process which involves pointing one telescope
axis to the North Star), the observer can track astronomical objects by turning
one control cable, instead of the two simultaneous motions required with
the altazimuth mount. If a small motor is attached to the equatorial mount,
this tracking can be performed automatically. These motor drives are
available for most Meade equatorially mounted telescopes.

With the equatorial mount of the Meade Model 395,
tracking astronomical objects is simplified.

Computer-Controlled Telescope Mountings

In 1992 Meade Instruments announced a revolutionary telescope
mounting concept that soon became the largest-selling telescope mounting
in the world among serious amateur astronomers. The Meade LX200
computer control system permits the telescope to be mounted in an
altazimuth orientation, while motors, directed by an internal
microprocessor, on both telescope axes follow astronomical objects with
extreme precision. The LX200 system further allows the observer to input
an object's catalog number or celestial position to a handheld keypad,
press GO TO, and watch as the telescope automatically moves to the
object and centers it in the telescope's field of view.

The 8" LX200's computer automatically locates over 64,000 c

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