NOTE: Instructions for the use of optional accessories
are not included in this manual. For details see the
Meade General Catalog.
The Meade Schmidt-Cassegrain Optical System (Diagram not to scale)
In the Schmidt-Cassegrain design of the Meade 16” model, light
enters from the right, passes through a thin lens (correcting plate)
with two-sided aspheric correction, 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 16” model includes an oversize 16.375” primary mirror,
yielding a fully illuminated field-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
p r i m a r y. This phenomenon results in Meade 16” Schmidt-
Cassegrains having off-axis field illuminations 10% greater,
aperture-for-aperture, than other Schmidt-Cassegrains utilizing
standard-size primary mirrors.
