Astronomy Technologies ASTRO-TECH AT8RCS Quick Start Manual

astro-tech
A T 8 RC S
Thank you for choosing this Astro-Tech AT8RCS 8" f/8
Ritchey-Chrétien astrographic reflector.
Your AT8RCS is designed for coma-free imaging using
DSLRs and CCD cameras. It is particularly good with systems
involving long imaging equipment chains (CCD camera, filter
wheel, adaptive optics system, electric focuser, etc.)
Vixen-style
dovetail
Collimation Secondary mirror
screws holder and baffle
PARTS OF THE AT8RC
Astro-Tech AT 8RCS Ritchey-Chrétien Astrograph Specifications
Aperture .................................................... 203mm (8")
Focal Length .................................................. 1625mm
Focal Ratio ............................................................... f/8
Optical Type .............................. dual hyperbolic mirror
Mirrors .......................... low thermal expansion quartz,
96% reflectivity aluminum coatings, quartz overcoat
Secondary Mirror Holder Obstruction ............. 95mm
(47% by diameter, 22% by area)
Field Stops .................... ten internal knife-edge baffles
Back Focus ...................... 10" (254mm) from rear cell,
6.25" (159mm) with standard focuser installed
Tube Diameter ............................... 9.02" (229mm) o. d.
Tube Length
(without focuser)
Components of the Focusing System: Your AT8RCS
has a linear bearing 2" Crayford focuser with a 2" compres-
sion ring accessory holder on the focuser drawtube. There is
also a separate 1.25" compression ring accessory holder that
can be slipped into the drawtube's 2" holder. These allow you
to use either 1.25" or 2" photographic accessories with no
other adapters needed.
To minimize drawtube flexure under heavy loads, the draw-
tube travel of the removable AT8RCS focuser is kept short, at
50mm. To make up for the long back focus and lengthy draw-
Mounting shoe for
optional finder
Lock knob
for focuser
drawtube
2" compression
ring accessory
holder
Left coarse
focus knob
2" accessory
lock knobs
Drawtube
tension knob
(underneath)
true Ritchey-Chrétien reflector
................ 18.5" (470mm)
from Astronomy Technologies
These instructions 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 quality imaging.
Please familiarize yourself with your astrograph's parts and
functions before operating it for the first time.
Locking collar for
removable 360°
rotatable focuser
Right coarse Fine
focus knob focus
knob
ring accessory adapter
Tube Length
(with focuser)
Tube Weight
(without focuser)
Tube Weight
(with focuser)
Mounting System ........ one 15.5" Vixen-style dovetail,
one 15.5" Losmandy-style "D-plate" dovetail
Focuser ............ removable dual-speed linear Crayford
2" and 1.25" compression ring accessory holders;
360° rotating camera angle/observing angle adjuster
Focuser Mounting Thread ......... 90mm x 1mm metric
Focuser Travel ....................................... 1.97" (50mm)
Focuser Extension Rings ....... two 25mm, one 50mm
Finder ........ none; mounting shoe provided for optional
Astro-Tech multiple reticle finder or similar finder
tube travel found in scopes used both visually and for imag-
ing (typically 80mm to 135mm or more), the AT8RCS focus-
ing system has several components, as shown in the illustration
on the next page. They consist of a removable 2" linear bear-
ing Crayford focuser that is threaded onto the scope's rear
cell when you receive your AT8RCS and three thread-on ex-
tension rings (two 1" and one 2"). The rings are designed to
be installed singly or in combination between the focuser and
the AT8RCS rear cell. They provide a flex-free solid metal
focuser extension to take up any unneeded back focus.
1
Vixen-style
dovetail on
top of tube;
Losmandy-style
underneath
1.25" compression
....................... 22" (560mm)
............. 17.4 lbs. (7.9 kg)
................ 18.9 lbs. (8.59 kg)
with 10:1 reduction ratio fine focus;
"D-plate"
dovetail
Thread-on
extension
rings