Focusing - Celestron StarSense Explorer DOBSONIAN Instruction Manual

FOCUSING

The SSE Dobs come with a 2" Crayford focuser, a 2"
extension tube, and a 2"-to-1.25" eyepiece adapter.
With these three items, you can use virtually any telescope
eyepiece with the SSE Dob.
For most eyepieces, make sure the 2" extension tube
is in place in the focuser. If it's not, the eyepiece will not
reach focus. If you're using an eyepiece that requires a lot of
inward focus travel, remove the 2" extension tube. You may
need to remove the tube if attempting to use your Dob with
an astronomical imaging camera.
If you wish to use a 1.25" format eyepiece, you'll need to
use the 2"-to-1.25" eyepiece adapter. Simply place it in the
focuser (with 2" extension tube attached), and then place
the 1.25" eyepiece in the adapter. Tighten the thumbscrew
on the adapter to secure the eyepiece in place. The adapter
uses an internal brass compression ring so your eyepiece
barrel won't be scratched or marred.
To focus, turn the focus knobs clockwise or counterclockwise
until the object in the telescope eyepiece is in sharp focus.
To lock the focuser position in place once you have achieved
sharp focus, tighten the focus lock thumbscrew (Figure
5). If you need to adjust the focus knob's tension, you can
tighten or loosen the focuser tensioning set screw using the
provided hex key.
Figure 5: The focus lock thumbscrew locks the focuser in place once
focus has been achieved. The focus tensioning set screw adjusts the
tension of the focusing knobs.
8 I ENGLISH
FOCUS LOCK
THUMBSCREW
FOCUSER
TENSIONING
SET SCREW
Since the SSE Dob is a Newtonian reflector, the images
you'll see will appear upside-down as compared to the
naked eye (Figure 6). While this has little impact on
astronomical observing, it can be a bit confusing when you
are viewing land-based objects.
NAKED EYE VIEW
VIEW THROUGH NEWTONIAN REFLECTOR TELESCOPE
Figure 6: Like all Newtonian reflectors, the SSE Dobs produce images
that appear upside-down as compared to the naked eye.