5
more than one rings depends on your equipment.
(3) Once you have threaded on the desired number
of extension rings onto the male threads on the
telescope tube, re-attach the focuser by aligning
the silver attachment collar over the exposed
extension ring threads and tighten by carefully
turning clockwise.
Be careful not to cross-thread any of the focuser
components when and if changing them in the
dark.
It may be useful to experiment with different
combinations during the day before heading out into
the field. Choose a target over half a mile away to
ensure you are simulating infinity focus. The goal is to
reach focus with as little extension of the focuser
drawtube as possible, to avoid drawtube flexure.
Depending on what equipment you use to observe or
image with, such as focal reducer or flattener, filter
wheel, or off-axis guider, you may need to add one or
more of the included extension rings.
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.
The fans pull outside air in through the rear cell and
blow it onto the back of the primary mirror and out the
front of the telescope. It’s best to point the telescope
upward when the fans are on to allow the heat to
more efficiently escape. The fans require a 12V
power supply; a battery holder using 8 AA batteries is
Cooling fan
12V DC in
