astro-tech
AT 1 1 1 EDT
from Astronomy Technologies
Thank you for choosing this
Astro-Tech AT111EDT
high-quality apochromatic triplet refractor.
The lenses in your scope’s 777mm f/7 air-spaced triplet
optics use Ohara glass exclusively, from Japan’s finest
glass manufacturer. They include an advanced ED (Extra-
low Dispersion) element to give you images that are
virtually color-free, even at very high powers. Thanks to
its computer-optimized optical design, top quality ED
Aperture
............................................ 111mm (4.4”)
Focal Length
...............................................777mm
Focal Ratio
........................................................ f/7
Objective Type
.............................. air-spaced triplet
using all-Ohara glass, including an ED element
Optical Coatings
........................... fully multicoated
Resolving Power
(Dawes’ Limit)
....... 1.04 arc seconds
Visual Limiting Magnitude
.............. 12.7 maximum
Light Grasp
(versus the eye)
.............................. 251x
Field Stops
.......................... three knife-edge baffles
Focuser
.......................... dual-speed rack and pinion
with 11:1 reduction ratio fine focus;
360° rotating camera angle/observing angle adjuster;
and 2” and 1.25” compression ring eyepiece holders
Focuser Travel
................................. 5.4” (138mm);
millimeter scale on drawtube for repeatable focus
glass, and high transmission multicoatings, the optical
performance of your AT111EDT is exceptional indeed.
This instruction sheet will provide you with information
on how to get the most out of your new Astro-Tech
refractor, and how to properly maintain it so it can give
you a lifetime of observing enjoyment.
Please familiarize yourself with the parts and functions
of your AT111EDT before using it for the first time.
Astro-Tech AT111EDT Apochromatic ED Triplet Refractor Specifications
Finder
.............. optional; mounting shoe provided for
Astro-Tech multiple reticle finder or similar finder
Lens Shade
............................................ retractable
Lens Shade Outer Diameter
.......................150mm
Objective Lens Cover
.........................slip-on metal
Tube Diameter
.................................... 124mm o. d.
Tube Length
(lens shade retracted)
.....23.75” (603mm)
Tube Length
(lens shade extended)
........ 28” (711mm)
Optical Tube Weight
................. 14.65 lbs. (6.66 kg)
Case
............................. aluminum-frame foam-fitted
lockable hard case, with carrying handle
Case Dimensions
..........................28” x 10.25” x 9”
Lowest Usable Power
......... 19.4x (40mm eyepiece)
Highest Terrestrial Power
.......86x (9mm eyepiece)
Highest Practical Power
........ 194x (4mm eyepiece)
Theoretical Maximum
........ 222x (3.5mm eyepiece)
Retractable dew shield
Lock knob for
focuser drawtube
Locking knob for 360°
rotatable focuser
PARTS OF THE AT111EDT
Left coarse
focus knob
Fine
focus
knob
Focusing
scale on
focuser
drawtube
1.25”
eyepiece
holder
1.25” eyepiece
lock knob
Dust cover
1.25” eyepiece
lock knob
Brass compression ring
Right
coarse
focus
knob
1.25”
eyepiece
holder
Mounting shoe for
optional finder
2” eyepiece
lock knob
2”
eyepiece
holder
2”
eyepiece
holder
1.25”
eyepiece
holder
