astr o-tech AT80EDT
from Astronomy Technologies
Thank you for choosing our Astro-Tech AT 80 EDT high-
performance apochromatic triplet ED refractor.
While some observers might doubt that you can get
apochromatic performance from an 80mm scope that is
as inexpensive as the Astro-Tech AT80 EDT, we can say
only that seeing is believing.
The images from its fully-multicoated 560mm f/7 ED
(Extra-low Dispersion element) premium Ohara glass
triplet optics are virtually color-free, even at high
Aperture .............................................. 80mm (3.1”)
Focal Length ...............................................560mm
Focal Ratio ........................................................ f/7
Objective Type.............. triplet using Ohara ED glass
Optical Coatings ........................... fully multicoated
Resolving Power (Dawes’ Limit) ....... 1.45 arc seconds
Visual Limiting Magnitude .............. 12.0 maximum
Light Grasp (versus the eye) .............................. 131x
Field Stops ......... glare-reducing baffle in optical tube
Focuser ............................. dual-speed Crayford-type
with 11:1 reduction ratio fine focus;
2” and 1.25” compression ring eyepiece holders;
360° rotating camera angle/observing angle adjuster
Focuser Travel ................................... 3.1” (80mm),
millimeter scale on drawtube for repeatable focus
Lens Shade ............................................ retractable
magnifications. At its low price, we believe you will find
that the visual and photographic performance of your
AT 80 EDT triplet 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.
Astro-Tech AT80EDT Apochromatic Triplet Refractor Specifications
Objective Lens Cover ......................... slip-on metal
Tripod Mount .. removable combination L-bracket and
dovetail for direct mounting on Celestron, Meade,
and Vixen equatorial mounts; two 1/4”-20 thread
mounting holes for photo tripod use
Tube Diameter ...................................... 90mm o. d.
Tube Length (lens shade retracted)..... 17.75” (451mm)
Tube Length (lens shade extended) ... 20.25” (514mm)
Optical Tube Weight................... 6.75 lbs. (3.07 kg)
Case ............................. aluminum-frame foam-fitted
lockable hard case, with carrying handle
Case Dimensions .................22.25” x 12.75” x 8.25”
Lowest Usable Power ............ 14x (40mm eyepiece)
Highest Terrestrial Power ....... 80x (7mm eyepiece)
Highest Practical Power ........ 140x (4mm eyepiece)
Theoretical Maximum ........... 187x (3mm eyepiece)
Retractable
dew shield
Lock knob for
focuser drawtube
1/4”-20 thread
tripod mounting holes
in base of reversible
bracket
Combined equatorial mount
dovetail and L-bracket
tripod mounting shoe
PARTS OF THE AT80EDT
Left coarse
focus knob
Fine
focus
knob
Focusing
scale on
focuser
drawtube
2” eyepiece
lock knob
Dust cover
1.25” eyepiece
lock knob
Brass compression ring
Mounting point for
optional finder
1.25”
eyepiece
lock knob
2”
eyepiece
holder
Locking collar for 360°
rotatable focuser
1.25” eyepiece
lock knob
Fine
focus
knob
Right
coarse
focus
knob
1.25”
eyepiece
adapter
1.25”
eyepiece
adapter
Right
coarse
focus
knob
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