astro-tech
AT 1 1 1 E D T
from Astronomy Technologies
Thank you for choosing this Astro-Tech AT111EDT glass, and high transmission multicoatings, the optical
high-quality apochromatic triplet refractor.
The lenses in your scope’s 777mm f/7 air-spaced triplet
performance of your AT111EDT is exceptional indeed.
This instruction sheet will provide you with information
optics use Ohara glass exclusively, from Japan’s finest on how to get the most out of your new Astro-Tech
glass manufacturer. They include an advanced ED (Extra- refractor, and how to properly maintain it so it can give
low Dispersion) element to give you images that are you a lifetime of observing enjoyment.
virtually color-free, even at very high powers. Thanks to
Please familiarize yourself with the parts and functions
its computer-optimized optical design, top quality ED of your AT111EDT before using it for the first time.
PARTS OF THE AT111EDT
Locking knob for 360°
rotatable focuser
Mounting shoe for
optional finder
Focusing
scale on
focuser
Lock knob for
focuser drawtube
2”
eyepiece
holder
drawtube
1.25”
eyepiece
holder
Retractable dew shield
Fine
focus
knob
Brass compression ring
Dust cover
2”
Left coarse
focus knob
Right
coarse
focus
knob
eyepiece
holder
1.25”
eyepiece
holder
2” eyepiece
lock knob
1.25” eyepiece
lock knob
1.25”
eyepiece
holder
1.25” eyepiece
lock knob
Astro-Tech AT111EDT Apochromatic ED Triplet Refractor Specifications
Aperture............................................ 111mm (4.4”) Finder .............. optional; mounting shoe provided for
Focal Length ...............................................777mm Astro-Tech multiple reticle finder or similar finder
Focal Ratio ........................................................ f/7 Lens Shade ............................................ retractable
Objective Type.............................. air-spaced triplet Lens Shade Outer Diameter .......................150mm
using all-Ohara glass, including an ED element Objective Lens Cover .........................slip-on metal
Optical Coatings ........................... fully multicoated Tube Diameter .................................... 124mm o. d.
Resolving Power (Dawes’ Limit)....... 1.04 arc seconds
Tube Length (lens shade retracted).....23.75” (603mm)
Visual Limiting Magnitude .............. 12.7 maximum Tube Length (lens shade extended) ........ 28” (711mm)
Light Grasp (versus the eye).............................. 251x Optical Tube Weight................. 14.65 lbs. (6.66 kg)
Field Stops .......................... three knife-edge baffles Case ............................. aluminum-frame foam-fitted
Focuser .......................... dual-speed rack and pinion
lockable hard case, with carrying handle
with 11:1 reduction ratio fine focus; Case Dimensions ..........................28” x 10.25” x 9”
360° rotating camera angle/observing angle adjuster; Lowest Usable Power......... 19.4x (40mm eyepiece)
and 2” and 1.25” compression ring eyepiece holders Highest Terrestrial Power .......86x (9mm eyepiece)
Focuser Travel ................................. 5.4” (138mm); Highest Practical Power........ 194x (4mm eyepiece)
millimeter scale on drawtube for repeatable focus Theoretical Maximum ........ 222x (3.5mm eyepiece)
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