Instruction Manual Meade Instruments Corporation
Instruction Manual 7" LX200 Maksutov-Cassegrain Telescope 8", 10", and 12" LX200 Schmidt-Cassegrain Telescopes Meade Instruments Corporation NOTE: Instructions for the use of optional accessories are not included in this manual. For details in this regard, see the Meade General Catalog. (2) (1) (1) (2) Ray (2) 1/2° Ray (1) 8.218" (2) 8.016" (1) 8.0" Secondary 8.0" Mirror Focal Plane Secondary Primary Baffle Tube Baffle Field Stops Correcting Primary Mirror Plate The Meade Schmidt-Cassegrain Optical System (Diagram not to scale) In the Schmidt-Cassegrain design of the Meade 8", 10", and 12" models, 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 aspheric 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 8", 10", and 12" models include oversize 8.25", 10.375" and 12.375" primary mirrors, respectively, 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 8", 10", and 12" Schmidt-Cassegrains having off-axis field illuminations 10% greater, aperture-for-aperture, than other Schmidt-Cassegrains utilizing standard-size primary mirrors. The optical design of the 4" Model 2045D is almost identical but does not include an oversize primary, since the effect in this case is small.
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