Instruction manual

50
11.FOCUSSING AND TARGET SIGHTING
G
• When sighting the target, strong light shining directly into the objective lens may cause the
instrument to malfunction. Protect the objective lens from direct light by attaching the lens hood.
Observe to the same point of the reticle when the telescope face is changed.
PROCEDURE
1. Focus on the reticle
Look through the telescope eyepiece at a bright
and featureless background.
Turn the eyepiece screw clockwise, then
counterclockwise little by little until just before
the reticle image becomes focussed.
Using these procedures, frequent reticle
refocussing is not necessary since your eye is
focussed at infinity.
2. Sight the target
Loosen the vertical and horizontal clamps, then
use the sighting collimator to bring the target
into the field of view. Tighten both clamps.
3. Focus on the target
Turn the telescope focussing ring to focus on
the target.
Turn the vertical and horizontal fine motion
screws to align the target with the reticle.
The last adjustment of each fine motion screw
should be in the clockwise direction.
4. Readjust the focus until there is no parallax
Readjust the focus with the focussing ring until
there is no parallax between the target image
and the reticle.
& Eliminating parallax
This is the relative displacement of the target image with respect to the reticle when the
observer’s head is moved slightly before the eyepiece.
Parallax will introduce reading errors and must be removed before observations are taken.
Parallax can be removed by refocussing the reticle.