Astro-Tech AT80EDT Quick Start Manual

astro-tech A T 80 EDT
Thank you for choosing our Astro-Tech AT80EDT high-
performance apochromatic triplet ED refractor.
Thanks to the use of all premium Ohara glass and an
ED (extra-low dispersion) element in its fully-multicoated
560mm f/7 ED triplet optical system, AT80EDT images
are virtually color-free, even at very high magnifications.
We believe you will find the visual and photographic per-
PARTS OF THE AT80EDT
2"accessory
Drawtube
lock knob
lock knob
(1 of 2)
Fine Right Drawtube tension
focus coarse
knob under focuser
knob focus to compensate for
knob different accessory
Brass compression ring
Dust cover
Astro-Tech AT 80 EDT Carbon Fiber Refractor Specifications
Aperture .............................................. 80mm (3.1")
Focal Length ...............................................560mm
Focal Ratio ........................................................ f/7
Objective Type ............... tripet using Ohara ED glass
Optical Coatings ........................... fully multicoated
Resolving Power
(Dawes' Limit)
Visual Limiting Magnitude .............. 12.0 maximum
Light Grasp
(versus the eye)
Field Stops ... 2 glare-reducing baffles in optical tube,
Focuser ................... dual-speed linear drive Crayford
with 10:1 reduction ratio fine focus;
2" and 1.25" compression ring eyepiece holders
Focuser Travel .......... 1.97" (50mm), with millimeter
scale on drawtube for repeatable focus
Optical Tube Material .......................... carbon fiber
Your Astro-Tech AT80EDT carbon fiber body ED triplet re-
fractor is usable for day and night viewing, simply by adding a
star diagonal and eyepiece. Any brand of eyepiece can be used,
from a 40mm for the lowest practical magnification (14x) to a
3mm (187x) for high power use. A 2" compression ring eyepiece
holder on the focuser drawtube and a supplied 1.25" eyepiece
adapter let you use both 2" and 1.25" star diagonals and eye-
carbon fiber ED refractor from Astronomy Technologies
Dew shield Retractable
lock knob dew shield
90mm split rings,
with 1/4"-20 thread
mounting holes
top and bottom
loads
1.25" eyepiece
lock knob
......... 1.45 arc seconds
................................ 131x
one at front of dew shield
formance of your AT80EDT is little short of remarkable.
This instruction sheet will provide you with information
on how to get the most out of your new refractor, and
how to properly maintain your scope so it can give you a
lifetime of observing enjoyment.
Please familiarize yourself with your telescope's parts
and functions before operating it for the first time.
Mounting point for
optional finder
(1 of 2)
Left coarse
focus knob
1.25" accessory
lock knob
1.25" accessory
adapter
1.25"
accessory
adapter
Optical Tube Diameter ......................... 90mm o. d.
Tube Length
(lens shade retracted)
Tube Length
(lens shade extended)
Weight
(optical tube only)
Weight
(with rings and 1.25" adapter)
Lens Shade ... retractable carbon fiber, with lock knob
Objective Lens Cover ......................... slip-on metal
Mounting Rings ............ dual 90mm felt-lined hinged
split rings with 1/4"-20 thread mounting holes
Case ............................. aluminum-frame foam-fitted
lockable hard case, with carrying handle
Case Dimensions ........................... 22.5" x 7.5" x 9"
Lowest Usable Power ............ 14x (40mm eyepiece)
Highest Terrestrial Power ....... 80x (7mm eyepiece)
Highest Practical Power ........ 140x (4mm eyepiece)
Theoretical Maximum ........... 187x (3mm eyepiece)
pieces with no other adapter needed.
The focal length of the AT80EDT is ideal for low to medium
power wide-angle views of nebulas, open star clusters, large gal-
axies, and comets. Crisp views of the Moon and planets are also
routine at magnifications of 112x to 187x when seeing condi-
tions permit.
To calculate the magnification of your telescope and eyepiece
2"
Dust cap
accessory
lock knob
(1 of 2)
2" accessory
holder
......... 18.5" (470mm)
........ 21.4" (544mm)
.................. 5.85 lbs. (2.66 kg)
..... 7.25 lbs. (3.3 kg)
Drawtube
lock knob
Focusing
scale on
focuser
drawtube
Fine
focus
knob
Right
coarse
focus
knob