The hole requirements for the filter system is just a small square cutout on your OTA.
No other modifications need to be made to install the focuser.
The filter lever system rides up and down above the mounting surface, and can be flipped in
and out at any position.
Installing the filter is done inside of the OTA. The filter simply screws into the
If the focuser is racked the whole way down, it may allow the filter holder to bump
into the incoming light path. The small amount of diffraction it causes should not
be noticeable. Eps should not reach focus at the extreme end of the focusers range
anyway. It is recommended that focus is achieved somewhere in the normal range of
the focusers travel.
Swinging the filter in the OUT position will limit the amount of up travel that is
available in the focuser. In this example the mounting surface is 1/4" so the
normal 2" of focuser travel is restricted to 1 3/4" of travel with the filter in
the out position. Mounting bolts should not stick down into the OTA where the
filter swings out. We supply a recessed "T" nut and a short bolt to be used in
Please feel free to contact us if you have any questions.