Astro-Tech AT 12RC Manual

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A T 1 2 RC
Thank you for choosing this Astro-Tech AT12RC
12" f/8 Ritchey-Chrétien astrographic reflector.
Your AT12RC is designed specifically for exceptional
coma-free imaging using DSLR cameras and large-
format CCD cameras having up to a 35mm chip size
and larger. Because of its long back focus, it is particularly
good with systems involving long imaging equipment
chains (combining a camera, filter wheel, temperature-
Losmandy-style "D-plate" dovetail for mounting
accessories; an identical dovetail is under the
tube for installing scope on equatorial mount
Secondary mirror
collimating screws
No Focuser Supplied: Many astro-imagers already have a
premium focuser being used on another scope that they would
like to use for imaging, or they have a preference for one
particular focuser manufacturer over another. Rather than pre-
installing a focuser of our choosing, and to give you the most
flexibility in choosing your preferred brand of focuser for imaging,
no focuser is supplied with your AT12RC. This allows you to
choose your own focuser, depending on your preferences. One
popular choice is the dual-speed 3" Feather Touch #3015 rack
and pinion focuser, available from your Astro-Tech dealer.
The rear cell of the AT12RC has a male 117m x 1mm pitch
threaded port for attaching a focuser. The #3015 Feather Touch
focuser mentioned above normally comes with a 109mm threaded
collar for connecting to a scope. In its AT12RC configuration
(Feather Touch #FTF3015B-A), however, the #3015 requires a
#M117x1 Feather Touch tube adapter (Feather Touch #A30-
1903-40) to adapt the 109mm focuser body to the 117mm rear
cell. The #3015 focuser slips into this adapter and is held in
place by three large Delrin-tipped brass retaining knobs.
Only focusers with a maximum 1.5" drawtube travel, such as
the Feather Touch #3015, are recommended for use with the
compensating focuser, etc.)
This instruction sheet will provide you with 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.
Please familiarize yourself with your scope's parts and
functions before operating it for the first time.
PARTS OF THE AT12RC
Mounting shoe for
optional finder
Hinged
tube rings
Primary mirror
collimating
screws
Secondary mirror
(1 pair of 3)
holder and baffle
Astro-Tech AT12RC. For brands of quality focusers other than
Feather Touch, such as MoonLite, contact your focuser dealer or
the focuser manufacturer for the availability of an adapter to fit
the 117mm x 1mm port on the rear of the scope.
To fine-tune the 288mm back focus of the AT12RC to the
requirements of your focuser and imaging equipment train, two
threaded extension rings (each 50mm in length) are provided to
thread singly or in combination between the 117mm threaded
port on the rear cell of the AT12RC and the 117mm adapter that
fits the focuser of your choice. These extension rings provide a
flex-free solid metal extension that changes the distance between
your chosen focuser and the rear cell. This lets you accommodate
the varying back-focus requirements of DSLR-type camera
imaging versus long equipment train CCD imaging.
Mounting Your AT12RC: Dual split hinged mounting rings,
joined by two 14" Losmandy-style "D-plate" dovetail plates that
are bolted to the rings, are provided for installing the AT12RC
on an equatorial mount and mounting optional accessories (such
as rings for a photoguide scope) on top of the AT12RC. The
rings should be positioned so that one plate is underneath the
optical tube for installing the AT12RC directly on a suitable high
1
from Astronomy Technologies
Losmandy-style dovetail
Cooling fan
(1 of 3) connecting battery pack
for mounting
accessories
Focuser
connection
threads on
the baffle
tube
5mm DC input jack for