6
The Star Diagonal
:
The Stellarvue D1040Q diagonal uses a thick and accurate
1/10 wave low expersion quartz mirror with a 99% dielectric coating. These diag-
onals are assembled and tested here at Stellarvue to ensure they maintain your
telescope’s performance. Astronomers prefer mirror star diagonals over prisms
because they are sharper and provide the highest contrast. Mirror star diagonals
present an image that is right side up but reversed left to right. If you are new to
using an astronomical telescope this will take a little practice, but it is worth the
effort because it will allow you to see more detail at night.
If you wish to use your telescope during the day as a
high quality spotting scope you may purchase an
erecting prism. The erecting prism will provide a cor-
rectly oriented view through the eyepiece. While we
do not recommend an erecting prism for star gazing,
it will work exceedingly well during the daylight
hours.
SETTING UP FOR VISUAL USE
Now that you have securely attached the telescope to the mount, you will need to balance it in both axes. The
mount manual explains how to do this. If you are using an equatorial and/or go-to computerized mount, you
will need to align the telescope according to the mount manual to get it ready for use. Once the telescope is
balanced and the mount aligned, you are ready to observe!
Two additional optical components are necessary to be able to view through
your telescope at night: a star diagonal and an eyepiece.
* The star diagonal reflects the light 90 degrees. Without it the viewer would
be forced to look upward when viewing and this would be extremely
uncomfortable.
* The eyepiece is needed to focus and magnify the image.
The star diagonal is inserted into the focuser, and the eyepiece is then inserted into the star diagonal.
Stellarvue #D1040Q two inch
dielectric quartz star diagonal
Stellarvue #D1035 two
inch erecting prism.
1 1/4”
Adapter
Star
Diagonal
Eyepiece
2”
Adapter
Thumb
Screw
Loosen the three 2 inch adapter
thumb screws and remove the 1
1/4” adapter.
Install the star diagonal and
make sure it is held in place
tight by securing the three 2”
adapter thumb screws.
Insert the eyepiece into the star diago-
nal as shown. Make sure the thumb
screw on the diagonal holds the eye-
piece in place securely.
