command is "FIND OPTIMAL BFL". Turn off the scope when done. This will set the mirror
spacing for best performance, as established by the optical design.
Different secondary mirrors as seen from “the sky”. In any design
the collimation screws are always three, set 120° apart, and
bigger than others (tension screws, carter screws...)
. Touch nothing but the collimation screws, unless otherwise directed by
Officina Stellare technical service. In the simplest design (at left) there are only the collimation screws (the big central one is to
disassemble the mirror or move it longitudinally). In different designs, where a secondary mirror motor is installed, the motor can be
visible (center) or hidden (right). Collimation screws are always bigger and 120° apart (green arrows in the center and right photos). In
the center and right photo, the red arrows point to the four “tension” screws, locate 90° apart from each other. Please be sure to
identify and use the 3 collimation screws. Again, collimation screws are always bigger than other screws.
3. You will now use the Takahashi collimator. If you use the collimation eyepiece instead,
read the note at the end of this section. To use the Takahashi, remove the telescope
focuser and its flange, if present, and install the conical flange, provided with the
collimation kit. If the telescope design requires an adapter between the back plate and the
conical flange, this adapter is provided. See photos below.
Removing the focuser (top left) and his
flange (top center). Installation of the
adapter for the conical flange, if needed
(top right). Installation of the conical flange
(bottom left) and insertion of the Takahashi
collimator (bottom center).
Operator's left index finger is pointing to the
Takahashi white plastic “window”, that
needs some illumination for the collimator
to work properly.
4. Insert the Takahashi collimator (“Tak”, for short) in the conical flange and lock it in place.
Point the telescope to a well illuminated wall or to the daytime sky (NOT toward the Sun!).
If you work indoor, you may need to illuminate the white plastic “window” located on the
side of the Tak. A flashlight will do the job. If outdoor, ambient illumination should be
enough to use the Tak, if you point the plastic white window “up” (see also the following
images).
5.
Take a look to the photos in the next page. Sliding the focus of the TC from "full inside"
position out you will see at the beginning only an indistinct circle of light, then the sharp
black circular spot (embedded in the TC optics)
and moving the focus further
one or more
of the concentric circles painted on the secondary mirror.
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