Astro-Tech 66mm F6 FPL53 quadruplet astrographApochromatic quadruplet ED refractor optics: the objective lens is a 65mm (2.56") aperture, 390mm focal length, f/6 focal ratio triplet using an element of high quality FPL-53 ED (Extra-low Dispersion glass) to reduce spurious color halos and fringing to vanishingly low levels. In addition, there is a separate ED glass singlet lens at the rear of the optical tube that acts as a field flattener to eliminate the curved field typical of fast focal ratio doublet and triplet refractors. Stars are focused and point-like to the edges of the field. This built-in field flattener eliminates the need to buy the separate external field flattener that most refractors need to provide flat field images.
Fully multicoated optics: All lenses have the latest state-of-the-art antireflection multicoatings matched to their glass types on all air-to-glass surfaces for high light transmission and excellent contrast.
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 a neighbor's backyard security light. The 4.85 pound AT65EDQ measures a very compact 13.75" long with the dew shield retracted, and is only 15" long with it extended.
Dual speed 2" rack-and-pinion focuser with 2" accessory holder and 1.25" accessory adapter, both with compression rings: The precision-made rack-and-pinion focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with 10:1 reduction gear fine focusing ratio. This provides exceptionally precise image control during critical DSLR 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.
The 2" focuser drawtube terminates in a built-in camera angle adjuster as standard equipment. It is not an optional extra-cost accessory, as it is with some other scopes. The camera angle adjuster lets you rotate the 2" accessory holder to line up a camera in either a landscape or portrait orientation (or any orientation in between) . A knob on the camera angle adjuster lets you lock the focuser at whatever angle provides the most pleasing photographic composition.
The 57mm (2.25") travel 2" diameter focuser drawtube has a scale marked in 1mm increments so you can note individual focuser positions for easy return to the approximate correct focus when switching between visual use and photography or when switching between cameras. A lock knob under the focuser lets you lock in your photographic focus. The dual thumbscrew 2" drawtube has a 2" accessory holder that uses a non-marring soft brass compression ring to hold 2" accessories in place. The compression ring won't scratch the barrel of your accessories as an ordinary thumbscrew can.
A standard equipment 1.25" accessory adapter slips into the 2" accessory holder to let you use a 1.25" star diagonal, image erecting diagonal, or photo accessories. Like the 2" accessory holder, the 1.25" adapter also uses a non-marring soft brass compression ring to hold 1.25" accessories in place. If you are partial to 1.25" eyepieces and need an outstanding diagonal for this scope, consider the Astro-Tech 1.25" dielectric diagonal (#AT1D) . It's a Sky & Telescope Hot Product for 2007.
Tube finish: The optical tube and lens shade are finished in a durable textured powder coat, the same as that used on scopes three times the price of the AT65EDQ. The focuser and trim are black anodized.
Tube rings and dovetail: The AT65EDQ comes with a pair of felt-lined 80mm hinged split mounting rings with 1/4"-20 thread mounting holes in the top and bottom of each ring, plus a Vixen-style dovetail. Supplied mounting bolts let you install the rings on the supplied dovetail or on an optional Losmandy-style “D-plate" dovetail for using the AT65EDQ on an equatorial mount. They will also let you attach the rings to optional Vixen- or Losmandy-style dovetail adapters for piggybacking the AT65EDQ on top of a larger scope.
Other supplied accessories: A slip-on metal dust cap is standard. There is a dovetail shoe on the upper left side of the optical tube for installing an optional multiple reticle red dot finder such as the Astro-Tech #ATF, using a #ATFBV base.
Two year warranty: As an expression of the confidence Astronomy Technologies has in the quality of their products, the Astro-Tech AT65EDQ quadruplet astrograph is protected by a two-year limited warranty against flaws in materials and workmanship