What is an Off-Axis Newt?
An Off-Axis Newtonian is a reflecting telescope that
by design deflects the primary mirror’s reflected light slightly out of the
incoming lightpath accomplishing a reflecting type instrument with no
central obstruction. This type of specialized mirror is usually manufactured by first
grinding, polishing, and parabolizing a larger “Parent Mirror”. The “Parent
Mirror” is then cut into four smaller off-axis paraboloids (OAP). As an
example, the OA-4 F/10 starts out as a 10-inch F4 “Parent Mirror” and ends up
as (4) four-inch F/10 OAP`s. It is this
design which provides an unobstructed reflector without requiring a tilted
primary mirror.
