Product Catalog
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Optical Systems
EXHIBIT 3
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What is it? Any scope that uses a combination of lenses and mirrors.
What About It? German astronomer Bernhard Schmidt made the rst compound (also known as Catadioptric) telescope in 1930.
A Compound telescope combines the best features of a refractor and a reector into one compact telescope. Light travels through a
correcting lens at the top of the tube to a concave mirror at the bottom of the tube, back to a small secondary mirror behind the lens,
and is nally focused at the rear of the telescope. Their excellent optical performance, compact size, and relative aordability make
compound telescopes by far the most popular design in use today. To a true astronomer, their prole is every bit as familiar as the
long-tube refractor is to the novice. Only Meade compound telescopes feature oversized primary mirrors (see pg. 87).
Who Uses Them? Serious astronomers, astrophotographers, researchers, colleges, universities, public and private observatories all over
the world. Also casual observers who want a combination of research quality optics, large aperture, and portability.
For What? Premium astrophotography and observation of everything from the Moon and planets to faint deep sky nebulas, clusters
and galaxies. Scientic measurements. Discoveries of comets and supernovas. Very portable in small to medium apertures. Often
mounted permanently in apertures over 14". Smaller apertures practical for daytime land viewing.
Meade Scopes Available: Maksutov-Cassegrain: ETX PE 90mm and 125mm (pg. 2). Advanced Coma-Free: LXD75-ACF 8” (pg 41),
LX90-ACF 8"-12" (pg. 50) LX200-ACF 8"-16" (pg. 62), LX400 10"-16" and 20" (pg. 78).
Schmidt-Cassegrain: As today’s most widely used telescope design, the Schmidt-Cassegrain
dominates astronomy clubs and star parties. For an aordable, portable, and nearly perfect
all-around instrument, they are hard to beat. Quality models rival refractors in resolution
and are only a little more costly than reectors per inch of aperture. However, after 27 years
of continuous production, Meade has stopped producing Schmidt-Cassegrain optics in favor
of its superior Advanced Coma-Free optical systems.
Maksutov-Cassegrain: This design is much like the Schmidt-Cassegrain, but with a spherical
corrector lens. This makes an even more compact telescope. Maksutov’s are popular for
both their portability and their textbook-perfect optical performance. But they are dif-
ficult to make right. Meade ETX’s rank among the world’s top Maksutov-Cassegrains.
Advanced Coma-Free: A traditional Ritchey-Chrétien (RC) is a type of reflector that has
been the premium choice for astrophotography for the past half-century. You’ll find
the RC design in most of the world’s top observatories and NASA’s Hubble Telescope.
Unfortunately, Ritchey-Chrétiens are very expensive to build (their prices make cars
sound cheap). In 2004, Meade engineers developed a radical new design that makes
RC performance available to everyone. By using a spherical primary mirror, a full
aperture corrector lens, and a hyperbolic secondary mirror, Meade’s Advanced Coma-
Free (ACF) produces a coma-free, flat field-of-view. The ACF actually corrects for
astigmatism better than the original (RC) design. Without a degree in optical engineering,
what that means to you is that Meade’s Advanced Coma Frees make observatory-class
optics available for roughly one-fifth of what amateurs had to pay in the past.
a s t r o p h o t o g r a p h y : j a s o n w a r e / c o m e t h y a k u t a k e / m e a d e 6 " 1 5 2 e d a p o
TELESCOPES 101. A basic guide to optical systems.