This Astro-Tech AT70ED refractor has:
- 70mm f/6 fully multicoated doublet optics using FK-61 ED glass
- dual-speed 2" Rack and Pinion focuser
- 2" and 1.25" brass compression ring eyepiece holders
- Single ring with a foot that has a 1/4" 20 thread hole for easy attachment to a dovetail.
Length: 11.8" dewshield retracted
Weight: 4lbs 13.6 oz with the ring
The AT70ED is bringing ED optics to you at a fantastic price. You get a 2" Rack and Pinion focuser with a microfine 11:1 fine-focusing ratio finished in our Aston Martin Grey trim. You get a single ring with a built in foot. The foot has a 1/4" 20 thread hole for easy attachment to a photo tripod or a dovetail of your choice. The finely-machined Astro-Tech AT70ED comes with both 2" and 1.25" eyepiece holders using non-marring brass compression rings that won’t scratch your star diagonal or eyepiece barrels. The AT70ED also comes with a retractable dew shield to make it as compact as possible at a tad under one foot.
As with all Astro-Tech scopes, the AT70ED gives you fully-multicoated ED optics that are essentially free of the annoying halo of unfocused violet light (chromatic aberration) that mars the bright-object images of lesser scopes, despite the fast focal ratio, and even at very high magnifications.
Features of this Telescope . . .
ED doublet refractor optics: 70mm (2.8") aperture, 420mm focal length, f/6 focal ratio doublet optical system using an FK-61 ED (Extra-low Dispersion glass) element to reduce spurious color halos and fringing to vanishingly low levels.
Fully multicoated optics: The AT70ED 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.
Dew shield: A 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 the lens shade on a camera lens, when observing during the day or when there is excessive ambient light at night, such as a neighbor’s backyard security light. A slip-on metal dust cap for the dew shield is standard.
2" Rack and Pinion dual-speed focuser: The precision-made no-backlash dual speed 2" rack and pinion focuser is based off our EDT line of telescopes. Very smooth, and very robust. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with an 11:1 reduction gear microfine focusing ratio. This provides exceptionally precise image control during high magnification visual observing and critical 35mm or CCD imaging. The focus knobs have ribbed gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather.
Long focuser travel: The long 92mm (3.62") travel of the focuser drawtube helps keep the overall scope length reasonable for convenient travel and storage. The long drawtube length also permits switching between visual or photographic use with no add-on extension tubes needed. The drawtube has a scale marked in 1mm increments so you can note individual focuser positions for easy return to the correct focus when switching between visual use and photography. A drawtube lock knob underneath the focuser lets you lock in your photographic focus.
Compression ring eyepiece holders: The focuser’s drawtube terminates in a 2" eyepiece holder that uses a non-marring soft brass compression ring to hold a 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 soft brass compression ring to hold 1.25" star diagonals and accessories in place. If you are partial to 1.25" eyepieces and need an outstanding diagonal for this scope, consider the 99% reflectivity Astro-Tech 1.25" dielectric diagonal #AT1D. It's a Sky & Telescope Hot Product for 2007. An optional Astro-Tech 2" dielectric star diagonal #AT2D will give you the same 99% reflectivity performance with 2" eyepieces.
Tube finish: The optical tube and lens shade are finished in a white powder coat while he focuser and trim are finished in Aston Martin Grey.
The AT70ED comes in a well made 16" x 9.5" x 7" padded cordura nylon case to help keep your scope nice and safe.
