Astro-Tech AT80EDT f/6 ED Triplet Refractor OTA

For the backyard grab-and-go observer, for the Milky Way star field scanner, for the wide field imager, for the birder and terrestrial photographer the Astro-Tech AT80EDT 80mm f/6 ED triplet apo is the Swiss Army knife of refractors.

In 2024 we looked at the landscape of refractors and decided that somethings might need some improvements.  Optically the Astro-Tech EDT still provided what astronomers have come to love about our refractors...performance and value.  We just felt that some mechanical upgrades would be a welcome addition to them.  For the 80EDT it meant visiting the focuser, rings, and internal baffles.

This Astro-Tech AT80EDT has:

• 80mm f/6 fully multicoated triplet apochromatic optics using an FK-61 ED center element 
• a dual-speed 2.8" CNC rotatable rack-and-pinion focuser with 10:1 ratio fine focuser 
• an upgraded camera angle adjuster
• durable nylon soft carry case 
  
• retractable lens shade/dew shield
• dual hinged split tube rings
•  a Vixen-style dovetail
• dual vixen finder shoes on the focuser body
• a top mounted handle

For grab-and-go observing, Milky Way star field sweeping, and wide field astrophotography (as well an terrestrial observing and photography), many observers swear by a good fast focal ratio 80mm refractor. The 6.5 pound 80mm f/6 Astro-Tech AT80EDT ED triplet apo refractor is just that scope. It does it all.

The Astro-Tech AT80EDT's slow-polished triplet optics, FK-61 ED glass center element, and state-of-the-art optical multicoatings are even more impressive when you consider the package they come in. The finely-machined scope has a dual-speed 2.8" rack-and-pinion focuser with a microfine 10:1 fine-focusing ratio. A built-in camera angle adjuster lets you fine-tune the composition of your astrophotos and the orientation of your equipment. The supplied 2" and 1.25" eyepiece holders use non-marring compression rings that won't scratch your eyepiece barrels. It even comes with a finder shoe, tube rings, and a dovetail plate.

This feature-laden 80mm Astro-Tech AT80EDT ED triplet apochromatic refractor offers exceptional optical and mechanical performance and features at a very reasonable price. It will do just about anything you want to do with a truly portable scope. Let it into your telescope family and you may never want to let it go.

Features of this Telescope . . .

ED apochromatic triplet refractor optics: 80mm (3.15") aperture, 480mm focal length, f/6 focal ratio. It uses an ED (Extra-low Dispersion glass) center element to reduce spurious color halos and fringing to vanishingly low levels. All three lens elements are slow-polished for smooth surfaces, with less scattered light.

Fully multicoated optics: The triplet objective lens has the latest state-of-the-art antireflection multicoatings on all air-to-glass surfaces for high light transmission and excellent contrast. This can easily be seen by looking into the objective lens of the scope. Virtually no reflection of your face will be seen. It's a sure sign that the high transmission coatings are doing their job, by letting virtually all the light enter the scope, rather than reflecting some light back to your eye.

Internal light baffles: Contrast-enhancing knife-edge light baffles in the 90mm diameter optical tube provide truly dark sky backgrounds and high terrestrial contrast. The edges of the lenses are blackened to reduce internal reflections and further improve image contrast.  When we went with the new 2.8" CNC focuser in late 2024 we improved the baffle design as well.

Dew shield: A self-storing retractable dew shield slows the formation of dew on the lens in cold weather to extend your undisturbed observing time. It also improves the contrast, similar to the effect of the lens shade on a camera lens, when observing during the day or when there is excessive ambient light at night, such as from a neighbor's backyard security light.

Dual speed 2.8" rotating rack-and-pinion focuser: The precision-made CNC focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with a 10:1 reduction gear microfine focusing ratio. This provides exceptionally precise image control during high magnification visual observing and critical CCD imaging.

The focus knobs have ribbed gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather. The focuser drawtube has 75mm of travel and a millimeter scale on the drawtube to let you return to an approximate focus when switching between visual and photographic setups. A lock knob under the focuser lets you lock in your photographic focus.

The focuser also comes with two vixen style finder shoes attached to the focuser body as standard equipment.  This will allow you to mount a vixen finder bracket or any accessory that uses a vixen style finder bracket.

Compression ring eyepiece holders: The focuser's 2.5" drawtube terminates in a 2" eyepiece holder that uses a non-marring compression ring to hold the standard equipment 2" star diagonal and/or accessories in place. The compression ring won't scratch the barrel of your star diagonal and accessories as an ordinary thumbscrew can.

A supplied 1.25" accessory adapter slips into the 2" eyepiece holder to let you use a 1.25" star diagonal, image erecting diagonal, or photographic accessories. Like the 2" eyepiece holder, the 1.25" adapter also uses a non-marring compression ring to hold 1.25" star diagonals and accessories in place.

Built-in camera angle adjuster: The focuser drawtube's 2" eyepiece/accessory holder includes a built-in camera angle adjuster that lets you quickly adjust the angle of your camera for the best composition or to put the star diagonal at the most comfortable observing angle. A knob on the 2" eyepiece/accessory holder lets you unlock the camera angle adjuster, rotate it to the desired final angle, then lock it in place at whatever angle is most convenient for you. This camera angle adjuster is standard equipment, not an optional extra-cost accessory, as it is with some other scopes.

Optical tube: The very compact 15" long optical tube and focuser (17" long with lens shade extended) are finished in a durable white finish, with grey trim. There is a finderscope mounting shoe that accepts Vixen-style finderscope mounting brackets. The shoe can be mounted on either the top left or top right side of the focuser body. A slip-on metal dust cap is standard, as is a dust seal for the eyepiece holder.

Tube rings and dovetail: Dual split hinged tube rings are supplied for the 90mm o. d. optical tube. The rings are lined with white felt that will not stain the white finish of the scope over time, unlike the black felt supplied with other scopes. A 5.4" long Vixen-style dovetail is bolted to the tube rings. Optional Losmandy-style D-plate dovetails are available if your mount uses a wider Losmandy-style saddle.

Carry handle:  The AT80EDT also comes with a top mounted carry handle to make mounting and moving your telescope a breeze. The handle will also allow vixen style DVAs to mount to it so accessories can be added directly to the top.

Tech Details: