Meade AT80LE instruction sheet Objective Type, Resolving Power Dawes’ Limit, Focuser Travel

astro-tech AT80LE

Thank you for choosing our Astro-Tech AT80LE high- performance apochromatic doublet ED refractor.

Its carbon fiber tube and dew shield are exceptionally durable, with excellent thermal characteristics. The dew shield is oversized, with a 124mm o.d. compared to the 80mm lens diameter.

This assures that tube currents, which typically follow the walls of a telescope tube, will have a minimal effect on your images as the AT80LE cools down to ambient temperature. You can begin serious observing with an AT80LE sooner than you can with an aluminum tube 80mm doublet with a conventional dew shield design.

from Astronomy Technologies

The images from the AT80LE’s fully-multicoated 480mm f/6 ED doublet optical system (using premium Ohara glass and an FPL-53 extra-low dispersion element) are virtually color-free, even at very high magnifications. We believe you will find that the visual and photographic performance of your AT 80LE doublet 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.

PARTS OF THE AT80LE

	Fine		Retractable	Mounting points for
		Dew shield	dew shield
2” eyepiece	focus	lock knob		optional finder
lock knob	knob			Focusing
				scales on
				focuser
				drawtube

	Right coarse			Left coarse	Fine
1.25”	focus knob
				focus knob
			90mm split rings,		focus
eyepiece
		Lock knob			knob
lock knob	Tension		with 1/4”-20 thread	2” eyepiece
		for focuser
	adjustment		mounting holes
		drawtube		holder
			top and bottom		Right
	knob for
focuser drawtube				1.25” eyepiece	coarse
				adapter	focus
	Dust cover			1.25” eyepiece	knob
		Brass compression ring		lock knob
					Dust cap
		1.25” eyepiece		1.25”	2” eyepiece
					lock knob
		lock knob		eyepiece

adapter

Astro-Tech AT80LE Refractor Specifications

Aperture		80mm (3.1”)
Focal Length		480mm
Focal Ratio		f/6
Objective Type	doublet using Ohara FPL-53 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 ... 2 glare-reducing baffles in optical tube,

Focuser	one at front of dew shield
	dual-speed Crayford-style
with 10:1 reduction ratio fine focus;
2” and 1.25” compression ring eyepiece holders
Focuser Travel	2.9” (74mm), with millimeter
and inch scales on drawtube for repeatable focus
Optical Tube Material	carbon fiber

Optical Tube Diameter	90mm o. d.
Tube Length (lens shade retracted)	15.5” (394mm)
Tube Length (lens shade extended)	18.75” (476mm)
Weight (optical tube only)	5.15 lbs. (2.34 kg)

Weight (with rings and 1.25” adapter) ... 6.55 lbs. (2.98 kg) Lens Shade ... retractable carbon fiber, with lock knob

Objective Lens Cover	.........................		slip-on metal
Mounting Rings	dual 90mm felt-lined hinged
split rings with 1/4”-20 thread mounting holes
Case	aluminum-frame foam-fitted
lockable hard case, with carrying handle
Case Dimensions			20” x 7.5” x 9”
Lowest Usable Power	............	12x (40mm eyepiece)
Highest Terrestrial Power		80x	(6mm eyepiece)
Highest Practical Power		160x	(3mm eyepiece)
Theoretical Maximum	...........	160x	(3mm eyepiece)