6
Attaching Optional Finder
Scopes and guiding Solutions
Unlike other Ritchey-Chretien telescopes on the market,
Orion RCs feature two dovetail finder scope bases on oppo-
site sides of the telescopes’ vertical mid-line (refer to
Figure
1A), to allow maximum versatility of placement for optional
finder scopes, reflex sights, or a mini guidescope. Having two
dovetail bases gives you the option of placing a finder scope
on either the left or right side of the focuser, depending on
your preference, or of mounting both a red-dot sight and a
traditional achromatic finder scope on the telescope simulta-
neously. For imaging, you may even wish to install a small
Figure 6.
Two included finder scope dovetail bases allow
installation of an optional mini 50mm guidescope and autoguide
camera on one side of the focuser and an optional finder scope on
the other. (6" RC shown)
Figure 7.
Slotted plates on the top side of the 8" and 10" RCs
allow mounting of a guide scope for astrophotography or of another,
auxiliary telescope.
Figure 8.
The 10" RC is equipped with three integrated 12V DC
cooling fans, which are powered by user-supplied AA batteries
guidescope such as the Orion 50mm Mini GuideScope in one
of the dovetail bases along with a reflex sight or another finder
scope for visual use in the other, as shown in
Figure 6. The
choice is yours!
The 8" and 10" RCs also feature slotted universal dove-
tail bars on top of the tube (
Figure 7), custom designed by
Orion, to allow mounting of a guidescope or a DSLR camera
for piggyback photography, or even a second, piggybacked
telescope for visual use or imaging. The top bar on the 8" RC
is a Vixen-style bar while the bar on top of the 10" is a wider,
Losmandy-style bar. With two long slots and multiple through-
holes, these solid aluminum bars can be used to mount guide
scope rings or tube rings spaced apart by the distance you
need for your guide scope or second telescope. No other RCs
on the market are equipped with these versatile top-side uni-
versal mounting bars.
Mounting the Telescope
Orion Ritchey-Chretien astrographs each have a dovetail
mounting bar running the full length of the optical tube for
rigid attachment to a compatible equatorial mount saddle
plate. The 6" RC has a narrow, Vixen-style bar while the 8"
and 10" include a wide, Losmandy-style bar. The long length
of the dovetail bars makes it easy to balance the RC on the
declination axis by sliding the scope forward or back before
locking it down.
Cooling the Telescope
Before observing or photographing with your RC, you should
let it equilibrate to the outdoor temperature for an hour or more.
This will reduce thermal air currents inside the telescope that
could soften or blur your images, whether you’re doing visual
observing or astrophotography. Due to the size of its optics,
the 10" RC is equipped with three small DC cooling fans on
its rear cell to help accelerate the cool-down time (
Figure 8).
The fans pull outside air in through the rear cell and blow it
Power jack
Fans
