Meade LX10 Schmidt-Cassegrain Instruction Manual page 2

The Meade Schmidt-Cassegrain Optical System
In the Schmidt-Cassegrain design of the Meade LX10, light enters from the right, passes through a thin lens with 2-sided aspheric correction ("correcting
plate"), proceeds to a spherical primary mirror, and then to a convex secondary mirror. The convex secondary mirror multiplies the effective focal length
of the primary mirror and results in a focus at the focal plane, with light passing through a central perforation in the primary mirror.
The Meade LX10 includes oversize primary mirrors, with the primary mirror of this 8" telescope at 8.25" diameter, yielding fully illuminated fields-of-view
significantly wider than is possible with standard-size primary mirrors. Note that light ray (2) in the figure would be lost entirely, except for the oversize
primary. It is this phenomenon which results in Meade Schmidt-Cassegrains having off-axis field illuminations about 10% greater, aperture-for-aperture,
than other Schmidt-Cassegrains utilizing standard-size primary mirrors. Field stops machined into the inside-diameter surface of the primary mirror
baffle tube significantly increase lunar, planetary, and deep-space image contrast. These field stops effectively block off-axis stray light rays, λ.
® The name 'Meade'and the Meade logo are trademarks registered with the U.S. Patent Office and in principal countries throughout
the world. 'LX10' is a trademark of Meade Instruments Corporation.
© 1999 Meade Instruments Corporation.
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