| In addition to your savings when you buy this excellent scope, we will also automatically take an additional 10% off any Astro-Tech product or products bought at the same time. This offer is only good while our present scope inventory lasts. A review in the Telescope Buyer’s Guide in the September 2007 Astronomy magazine said about the Astro-Tech AT66ED, “While I’d normally have reservations about recommending a scope with less than 3 inches of aperture, every once in a while there comes a product everyone should own. This apochromatic doublet is just such a beast . . . The short focal length makes it a wonderful tool for scanning the Milky Way, and its small aperture and FPL-51 glass let you crank up the magnification on the Moon without false color becoming too intrusive. The AT66ED can serve as a great grab-and-go scope, a fine little astrograph, a super-finder scope, and a daytime spotting scope . . . The only real question is which of the available colors do you want?” This Astro-Tech telescope has: • 66mm f/6 fully multicoated ED glass apochromatic refractor optics
• dual-speed Crayford focuser with 11:1 ratio fine focusing
• combined dovetail/tripod bracket for use on a photo tripod or a German equatorial mount
• amazing wide field astrophotographic capabilities
• long-lasting hard anodized blue finish with black trim
• aluminum-frame foam-fitted hard case
• two-year warranty If you’re a Meade telescope owner, the anodized blue finish of this Astronomy Technologies Astro-Tech AT66ED refractor will make you feel right at home. And the color-free images of its outstanding ED (Extra-low Dispersion glass) optics will please your eye from your very first look and for years to come. Add superb mechanics to those outstanding optics, some unique features, and a startlingly low price, and this very economical telescope stands apart in an appearance and performance class of its own. The images from its 400mm f/6 ED air-spaced doublet optics are virtually free from spurious color (chromatic aberration), even at high magnifications. At its low price, the optical performance is little short of astonishing. While the manufacturer says the scope has apochromatic optics, we won’t claim it is a true apo in the class of a multiple thousand dollar Takahashi, Astro-Physics, or TMB refractor. However, this compact scope is so good you’ll probably swear it really is an apo. 
The wide field astrophotographic capabilities of this compact scope are little short of amazing for a scope in this price range. The links below are to some images of the North American Nebula taken by Sean Walker, Assistant Editor, Sky & Telescope magazine. He used an AT-66 he bought for his personal use and an SBIG STL-11000 CCD camera. He commented, “I expected the image to be a circle in the center of the chip, but the image looks great almost to the very corners. Of course, there is vignetting, but good flats took care of that. In reality, this scope can cover a KAF 6303 chip (4008 x 2672 pixels) comfortably . . . this scope is a keeper." This link will take you to a 1332 x 2000 pixel image of the entire field. This second link will take you to a 1603 x 2000 pixel high resolution crop of the center of the full field. Both images can be expanded to more than fill your computer screen.
Here are some further AT-66 images, taken by Joe Bruessow, and used with his kind permission. Joe used an SBIG ST2000XM CCD camera (about 40% the price of the camera used by Sean Walker for the image above). It was piggybacked on a 10" Newtonian optical tube installed on a Losmandy equatorial mount that Joe says “tracks like a champ." The links below will take you to the full-sized images. All of the full size images measure 900 x 1200 pixels.
The first image is a luminance image of the Pelican Nebula, also seen in color in Sean Walker’s North American Nebula image above. This link will take you to Joe’s full size image.
The second image is a tri-color shot of M-42, the Orion nebula. This link will take you to the full size image.
The third image is a tri-color image of the Horsehead and Flame Nebulas. Here’s the link to it.
The last image is the H-alpha luminance image only of the Horsehead and Flame. Here’s the link to the luminance image. Joe Bruessow commented that the H-alpha image was “not as deep or resolved as (a famous refractor designer’s image taken through one of his ultra-premium long waiting list scopes and widely published elsewhere) . . . but cost 1/30 of the price :o)" It sounds like the AT-66 is a bargain when compared to that famous name high end scope.
The exceptional AT66ED optics are even more impressive when you consider the package they come in. The finely-machined scope has a dual speed Crayford-style focuser with a microfine 11:1 fine-focusing ratio. A simple twist of a knurled ring on the scope body lets you rotate the focuser a full 360° to put your eyepiece in the most comfortable observing position. The supplied 1.25" eyepiece adapter uses a non-marring brass compression ring that won’t scratch your eyepiece barrels. The Astro-Tech AT66ED has a retractable lens shade and comes in a locking aluminum-frame hard carrying case. This 11.5" long refractor optical tube (14.25" long with the lens shade extended) has the right balance of aperture and focal length to use as a low-power rich field telescope, as a medium-power planetary telescope, or as any kind of telescope in between. Its compact size, light weight, and convenient removable L-shaped mounting shoe that fits any photographic tripod also make it an excellent terrestrial spotting scope for vacations, birding, or nature studies. In addition, optional camera adapters turn the AT66ED into a superb 400mm (8x) f/6 telephoto lens. The mounting shoe is also a dovetail adapter that will fit directly into the dovetail slot on the top of many German equatorial mounts, such as those from Celestron, Meade, and Vixen. If this Astronomy Technologies AT66ED was just another 66mm refractor, the quality of its optics alone would still make it a superb value. Add the unique features – like the dual speed microfine focuser, your choice of colors, and a hard case – and you have a scope that has absolutely no equal at its very affordable price. Features of this Telescope . . . - Apochromatic refractor optics: 66mm (2.6") aperture, 400mm focal length, f/6 focal ratio air-spaced doublet lens using premium Ohara glass from Japan, including an ED (Extra-low Dispersion glass) element to reduce spurious color halos and fringing to vanishingly low levels. While we do not claim fully apochromatic performance, as the manufacturer does, the scope is so free from spurious color as to be virtually indistinguishable from an apochromatic system. And, as Mr. Spock probably said in one episode of Star Trek or another, “Any difference that makes no difference, is no difference."
- Multicoated optics: The objective lens has the latest state-of-the-art broadband antireflection multicoatings on all four 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: There are ten contrast-enhancing light baffles in the optical tube, for truly dark sky backgrounds and high terrestrial contrast. In addition, the edges of the objective lens are blackened to eliminate contrast-reducing stray internal reflections.
- Full power range capability: The “highest useful magnification" listed above right is 133x. This is the power obtained with a 3mm eyepiece, which provides an exit pupil of 0.5mm (about 1/50th of an inch) and 51x per inch of aperture. This is generally the smallest exit pupil recommended with any telescope before the images start to become too dim to be consistently useful.
Higher powers are possible for lunar and planetary observing, however, given reasonable seeing conditions. We’ve used the AT66ED on Saturn with a 4.8mm TeleVue Nagler and a Burgess/TMB 1.9x Optical Corrector Assembly (Barlow). This equals an effective focal length of 2.53mm and a magnification of 158x (61x per inch of aperture). Spurious color was still vanishingly low and apo-like with this combination. The image was still sharp and contrasty, although relatively dim (as you would expect with a 66mm aperture). Still higher magnifications are probably possible under excellent seeing conditions, although the increasing dimness of the image will start to limit the performance on all but the brightest objects.
The lowest useful power is 10x, achieved with a 40mm eyepiece (a 40mm TeleVue Plössl will give you a 4.2° field at that power). At 3.85x per inch of aperture, this is close to the 4x per inch of aperture generally regarded as the lowest practical power with any telescope. A 40mm eyepiece on the AT66ED will give you a 6.67mm exit pupil, larger than most eyes can dilate. Any lower power would simply waste some of the scope’s light gathering capacity, as its collected light would fall on your iris, rather than entering your eye. - 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.
- Dual speed microfine Crayford-style focuser with 1.25" adapter: The precision-made focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with 11:1 ratio reduction gear microfine focusing. This provides exceptionally precise image control during visual observing or 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. The 60mm (2.36") travel focuser 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 lock knob under the focuser lets you lock in your photographic focus.
The focuser drawtube terminates in a standard 2" SCT-type rear cell thread to allow the use of any SCT photographic or visual accessory (2" SCT star diagonal, T-adapter, etc.) A locking ring on the body of the scope allows the focuser to be rotated a full 360°. This lets you rotate the focuser to line up a camera in either a landscape or portrait orientation (or any orientation in between), as well as put a star diagonal and eyepiece into the most comfortable observing position, and then temporarily lock the focuser in that position.
The supplied 1.25" eyepiece adapter threads onto the drawtube’s 2" SCT threads and uses a soft brass compression ring to hold 1.25" star diagonals and accessories in place. The compression ring won’t scratch the barrel of your star diagonal as an ordinary thumbscrew can. - Combined equatorial dovetail/tripod adapter: The AT66ED has a removable L-shaped dovetail mounting shoe/tripod adapter. The 1.75" wide x 2.85" long mounting shoe is sized and shaped (with slanted sides) to fit the dovetail slot on the head of many equatorial mounts. It will fit, without modification, Celestron CG-5 and Advanced Series mounts, Meade LXD-75 mounts, and Vixen Great Polaris and Sphinx mounts, among others.
In addition, the mounting shoe has 1/4"-20 thread mounting holes that allow it to be installed on any camera tripod that has a standard 1/4"-20 thread mounting bolt. The bracket has two tripod mounting holes to allow you to balance the weight of a camera or heavy 2" eyepieces and accessories. The front hole balances the scope for 1.25" diagonal and 1.25" eyepiece use with the lens shade extended. The rear hole balances it when a camera or a 2" diagonal and 2" eyepiece are mounted.
Cork pads on the underside of the mounting shoe help keep the scope from swiveling when mounted on a tripod. - Tube finish: The optical tube has an anodized Meade blue finish with anodized black trim that will blend in beautifully with a Meade SCT optical tube.
- Other supplied accessories: A slip-on metal dust cap is standard. A threaded hole for installing a finderscope mounting shoe is located on the left side of the scope body in front of the focuser lock ring.
- Shipping/storage case: The scope comes in a 15.25" x 9.75" x 7.25" aluminum-frame locking hard case with carry handle. The foam-fitted case has cutouts for the scope, a 1.25" or 2" star diagonal, and up to three eyepieces (two 1.25" and one 2").
Astro-Tech is one of the very few manufacturers to provide a case at no charge for protection during shipping and as a storage convenience when the scope is not in use. Unfortunately, FedEx, UPS, and the Postal Service are very good at treating packages roughly. Occasionally, your scope can arrive in perfect condition, but with the walls of the shipping case dented in transit from rough handling, or the aluminum frame sprung, rendering the appearance of the case less than pristine. Damage to the shipping case in such instances is not covered by warranty. - Two year warranty: As an expression of the confidence Astronomy Technologies has in the quality of their products, the Astro-Tech AT66ED is protected by a two-year limited warranty against flaws in materials and workmanship (shipping case excluded).
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