Meade instruction manual Astro-Tech AT66ED Apochromatic Refractor Specifications, Focuser

astro-tech AT66ED

from Astronomy Technologies

Thank you for choosing this Astro-Tech AT66ED high- quality compact apochromatic refractor.

While some observers might doubt that apochromatic performance can be had in a 66mm scope that costs as little as the AT66ED, we can say only that seeing is believing.

The images from its 400mm f/6 ED (Extra-low Dispersion glass element) air-spaced doublet optics are virtually color- free, even at high magnifications. At its low price, we believe

you’ll find that the optical performance of your AT66ED is little short of astonishing.

This instruction manual will provide you with information on how to get the most out of your new telescope, and how to properly maintain your telescope 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.

PARTS OF THE AT66ED	Locking collar for 360°	Mounting point for
	rotatable focuser	optional finder
Retractable dew shield
		Thread-on	Focusing
			scale on
		1.25”
			focuser
		eyepiece
			drawtube
		adapter

Astro-Tech

1/4”-20 thread	Lock knob		Fine
tripod mounting holes	for focuser drawtube	Left coarse
			focus
in base of bracket	underneath body
		focus knob	knob
Combined equatorial mount
			Right
Dust cover	dovetail and L-bracket
		Dust	coarse
	tripod mounting shoe
		cap	focus
	Brass compression ring		knob
	1.25” eyepiece		1.25” eyepiece
		Thread-on 1.25”	lock knob

lock knob	eyepiece
	adapter

Astro-Tech AT66ED Apochromatic Refractor Specifications

Aperture	66mm (2.6”)
Focal Length	400mm
Focal Ratio	f/6

Objective Type .... air-spaced doublet with ED element

Optical Coatings	fully multicoated
Resolving Power (Dawes’ Limit)	1.75 arc seconds
Visual Limiting Magnitude	11.6 maximum
Light Grasp (versus the eye)	89x

Field Stops .... 10 glare-reducing baffles in optical tube

Focuser	............................... dual-speed Crayford-type
	with 11:1 reduction ratio fine focus;

360° rotating camera angle/observing angle adjuster; and thread-on 1.25” compression ring eyepiece holder

Focuser Travel 2.4” (60mm)

with millimeter scale on drawtube for repeatable focus

Lens Shade retractable

Objective Lens Cover ............................. slip-on metal

Tripod Mount ... removable combination L-bracket and dovetail with 1/4”-20 thread mounting holes for photo tripod use as well as direct mounting on Celestron, Meade, and Vixen German equatorial mounts

Tube Diameter			75mm o. d.
Tube Length (lens shade retracted)			..... 11.5” (292mm)
Tube Length (lens shade extended)			..... 14.4” (366mm)
Optical Tube Weight			3.9 lbs. (1.8 kg)
Case	aluminum-frame foam-fitted
lockable hard case, with carrying handle
Case Dimensions			15” x 9.5” x 6.25”
Lowest Usable Power	10x (with 40mm eyepiece)
Highest Terrestrial Power	... 67x	(with 6mm eyepiece)
Highest Practical Power ....	100x	(with 4mm eyepiece)
Theoretical Maximum	133x	(with 3mm eyepiece)