Celestron C8-N Telescope User Manual


 
45
If you have an eyepiece in the focuser, remove it. Rack the focuser tube in completely, using the focusing knobs,
until its silver tube is no longer visible. You will be looking through the focuser at a reflection of the secondary
mirror, projected from the primary mirror. During this step, ignore the silhouetted reflection from the primary
mirror. Insert the collimating cap into the focuser and look through it. With the focus pulled in all the way, you
should be able to see the entire primary mirror reflected in the secondary mirror. If the primary mirror is not
centered in the secondary mirror, adjust the secondary mirror screws by alternately tightening and loosening them
until the periphery of the primary mirror is centered in your view. DO NOT loosen or tighten the center screw in the
secondary mirror support, because it maintains proper mirror position.
Aligning the Primary Mirror
Now adjust the primary mirror screws to re-center the reflection of the small secondary mirror, so it’s silhouetted
against the view of the primary. As you look into the focuser, silhouettes of the mirrors should look concentric.
Repeat steps one and two until you have achieved this.
Remove the collimating cap and look into the focuser, where you should see the reflection of your eye in the
secondary mirror.