Focusing - Takahashi Mewlon-180C Instruction Manual

After an eyepiece has been attached on your telescope, precise focusing is needed to
observe objects and landscapes clearly. If not correctly focused, your telescope cannot
display its capabilities. Precise focusing is absolutely necessary especially in astro-imaging.
Always use the best possible focus with the following procedures.
◆ Focusing System
Focusing this optical system is done by
moving the primary mirror forward and
backward using the focusing knob. The
relation of the motion direction of the
primary mirror and the focal point is as
illustrated below.
When the focusing knob is turned counter-
clockwise (OUT), the primary mirror is
moved toward the secondary and then, the
focal plane is moved outward. When the
focusing knob is turned clockwise (IN), the
primary mirror is moved toward mirror cell
and then, the focal plane is moved inward.

Focusing

The optical axis of the Mewlon-180C
could become decollimated if the
Mewlon is subjected to strong shocks
during transport. In order to prevent
the telescope from decollimating, the
primary mirror is moved to the mirror
cell. So, when focusing, turn the
focusing knob in the OUT direction
(counter-clockwise).
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Caution
OUT
Focal Plane
Focal Plane
IN