Astro-Tech AT 12RCT Manual

astro-tech
A T 1 2RC T
Thank you for choosing the Astro-Tech AT12RCT
12" f/8 Ritchey-Chrétien Serrurier truss reflector.
This newest version of the AT12RCT is designed
specifically for exceptional coma-free imaging using
DSLR cameras and large-format CCD cameras having
up to a 35mm equivalent chip size. Because of its
long back focus, it is particularly good with systems
involving long imaging equipment chains (combining
Losmandy-style "D-plate" dovetail for mounting
accessories; an identical dovetail is under the
tube for installing scope on equatorial mount
Primary mirror
baffle tube
Secondary mirror
collimating screws
Front truss-tube
support rings
Focuser: The AT12RCT comes with a dual-speed linear
bearing Crayford focuser for use with light imaging trains (such
as a DSLR body only). However, a very heavy multi-component
imaging train would probably require an upgrade to a rack-
and-pinion focuser to support the extra weight. Alternatively,
you may already have a premium focuser from another scope
that you would like to use, or you may want to install a robo-
focus for use at a remote observatory.
The supplied Crayford focuser can be unthreaded from the
focuser attachment collar, allowing you to substitute your own
focuser. One premium focuser that is used by many
astrophotographers is the dual-speed 3" Feather Touch #3015
rack and pinion. Focusers with a 1.5" drawtube travel, such
as the Feather Touch #3015, are recommended.
The back plate of the AT12RCT has a male 117mm x 1mm
pitch threaded attachment collar for installing a focuser.
However, the standard #3015 Feather Touch focuser has a
109mm female threaded collar for connection to a scope.
Feather Touch has designed a special version of the #3015
specifically for the AT12RCT (their part #FTF3015B-A). It
substitutes a #M117x1 tube adapter for the usual 109mm
threaded collar of the #3015. The #M117x1 adapter threads
a camera, filter wheel, robo-focuser, etc.)
information on how to get the most out of your new
Ritchey-Chrétien reflector, and how to properly
maintain your telescope so it can give you a lifetime
of high quality imaging enjoyment.
and functions before operating it for the first time.
PARTS OF THE AT12RCT
Rear truss-tube support
Center truss-tube
support ring
Finder shoe
Cooling fan
(1 of 3)
Primary mirror
collimating
screws
(1 pair of 3)
18-point mirror
floatation system
(inside back plate)
5mm DC input jack for
connecting battery pack
Primary mirror
light shield
Secondary mirror
Supplied focuser
holder and baffle
onto the AT12RCT attachment collar. The #3015 focuser slips
into the adapter, where it is held in place by three large Delrin-
tipped brass retaining knobs.
Touch #A30-1903-40) for those who may want to use their
existing 109mm threaded #3015 focuser on the AT12RCT.
For focusers other than Feather Touch, such as a MoonLite,
contact your telescope dealer or the focuser manufacturer
for an adapter to fit other brands of focusers to the 117mm x
1mm thread attachment collar on the rear of the scope.
requirements of your focuser and imaging equipment train,
three 117mm diameter threaded extension rings (one 50mm
in length, and two 25mm) are provided. These thread singly
or in combination between the 117mm attachment collar on
the AT12RCT back plate and the 117mm adapter that holds
the focuser of your choice.
that changes the distance between your chosen focuser and
the back plate. This lets you accommodate the varying back-
focus requirements of DSLR-type camera imaging versus long
equipment train CCD imaging.
1
from Astronomy Technologies
This instruction sheet will provide you with
Please familiarize yourself with your scope's parts
Losmandy-style "D-plate"dovetail
ring (back plate) for mounting accessories
Battery pack
The #M117x1 adapter is also available separately (Feather
To fine-tune the 260mm back focus of the AT12RCT to the
The extension rings provide a flex-free solid metal extension
Focuser
attachment
collar
Extension
rings (3)