astro-tech
AT 9 0 E D T from Astronomy Technologies
Thank you for choosing this Astro-Tech AT90EDT of your AT90EDT is little short of astonishing.
high-performance apochromatic ED triplet refractor.
This instruction sheet will provide you with information
The images from its fully-collimatable 600mm f/6.7 on how to get the most out of your new refractor, and
ED (Extra-low Dispersion) air-spaced triplet optics are how to properly maintain your telescope so it can give
virtually color-free, even at high magnifications, thanks you a lifetime of observing enjoyment.
to its use of advanced Ohara FPL-53 ED glass. At its
Please familiarize yourself with your telescope’s parts
price, we believe you’ll find that the optical performance and functions before operating it for the first time.
PARTS OF THE AT90EDT
Mounting shoe for
optional finder
Lock knob for 360°
rotatable focuser
Focusing
scale on
focuser
2”
drawtube
Lock knob for
focuser drawtube
eyepiece
1.25”
holder
eyepiece
Retractable dew shield
holder
Fine
focus
knob
Mounting shoe for
optional finder
Left coarse
focus knob
Brass compression ring
Dust cover
2”
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 AT90EDT Apochromatic ED Triplet Refractor Specifications
Aperture............................................ 90mm (3.54”) Finder ................mounting shoe provided for optional
Focal Length ...............................................600mm Astro-Tech multiple reticle finder or similar finder
Focal Ratio ......................................................f/6.7 Lens Shade ............................................ retractable
Objective Type........... collimatable air-spaced triplet Lens Shade Outer Diameter .......................130mm
using Ohara FPL-53 ED glass Objective Lens Cover .........................slip-on metal
Optical Coatings ........................... fully multicoated Tube Diameter .................................... 114mm o. d.
Resolving Power (Dawes’ Limit)....... 1.29 arc seconds
Tube Length (lens shade retracted)...... 18.9” (480mm)
Visual Limiting Magnitude ..............12.3 maximum Tube Length (lens shade extended) ....21.75” (552mm)
Light Grasp (versus the eye).............................. 165x Optical Tube Weight...................11.45 lbs. (5.2 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 9” x 9”
2” and 1.25” compression ring eyepiece holders; Lowest Usable Power............ 15x (40mm eyepiece)
360° rotating camera angle/observing angle adjuster Highest Terrestrial Power .......85x (7mm eyepiece)
Focuser Travel .................................. 4.7” (120mm) Highest Practical Power........ 150x (4mm eyepiece)
with millimeter scale on drawtube for repeatable focus Theoretical Maximum ........... 200x (3mm eyepiece)
|