Astro-Tech AT92 f/5.5 Triplet Apo Refractor OTA


Availability: Out of stock

If you are looking for the best fast focal ratio/compact APO refractor that Thomas Back and Roger Ceragioli could create, then look no further.
Our Product #: AT92
Astro-Tech Product #: AT92
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Product Description

This Astro-Tech AT92 refractor has:

• 92mm f/5.5 apochromatic triplet optics using an ED/Lanthanum combination
• collimatable lens cell for peak imaging and optical performance
• 2.5" dual-speed rotating rack and pinion focuser
• ultra-short 16.5" length for travel
• 2" and 1.25" compression ring eyepiece holders
• retractable dew shield, dust covers, and 20.5"x9.5"x9" hard case
• CNC tube rings and a Vixen dovetail

The AT92 92mm f/5.5 triplet apo is a very compact refractor for the serious observer and traveler. Measuring only about 16.5" long with the focuser and dewshield retracted for storage and travel, the AT92 optically and mechanically fills the void left by the discontinued TMB-92 and 90mm f/5 Astro-Physics Stowaway (a legendary scope that sells for up to $6000 on the used market).

The AT92 puts exceptionally high optical and mechanical quality in a truly tiny package. It is ideal for the serious observer who will accept nothing less than unsurpassed imaging and visual observing performance in a supremely portable body you can take with you anywhere in the world.

The AT92 is a continuation of the legendary TMB92. Thomas laid the foundation for this scope when we had him design his ultimate refractor, the TMB-92 Signature Series. The design has set dormant in our "vault" for the past 5 years or so until we thought it was time to dust it off. We sent the design to Roger Ceragioli to give it a once over and make sure that it was performing as it should with advances in glass and coatings over the last decade. He studied it, and made some changes to try and get every ounce of performance possible out of 92mm of glass.

The AT92 is an exceptional grab and go scope for observing and imaging - both within the solar system and out to the furthest reaches of infinity. Its images of subtle low-contrast lunar and planetary details are razor-sharp, with realistic and highly saturated color. Those images are free from chromatic aberration of any type, thanks to the ED element in the scope's triplet optics.

The latest antireflection multicoatings and knife-edge internal baffles assure the maximum image contrast possible. Image excellence is limited only by the seeing conditions, not by any aberration or short-coming in the telescope.

This Telescope's Optical and Mechanical Systems . . .

Apochromatic triplet ED refractor optics: 3.6" (92mm) aperture, 506mm focal length, f/5.5 triplet lens. It uses an ED (Extra-low Dispersion) glass center element in combination with a rear Lanthanum element for a sharp images that are high in contrast and free from spurious color (chromatic aberration).

Multicoated optics: Fully multicoated on all surfaces with the latest antireflection materials for exceptionally high light transmission and excellent contrast. Light transmission is so high that the optics seem to virtually disappear when viewed from head on.

Internal light baffles: Contrast-enhancing knife-edge light baffles in the optical tube and focuser provide 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.

Retractable dew shield: The self-storing retractable dew shield/lens shade slows the formation of dew on the lens to extend your undisturbed observing time. It also improves visual and photographic contrast by shielding the lens from off-axis ambient light (the neighbor's yard light, moonlight, etc.)

Dual-speed 2.5" rotating rack and pinion focuser: The precision-made 2.5" 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 very high magnification visual observing, and during critical 35mm or CCD imaging. All focus knobs are ribbed, so they are easy to operate, even while wearing gloves or mittens in cold weather. Multiple internal baffles in the focuser drawtube assure high contrast.

Compression ring eyepiece holders: The focuser drawtube ends in a 2" eyepiece holder that uses a non-marring soft brass compression ring to hold a 2" star diagonal and accessories in place. The compression ring won't scratch the barrel of your star diagonal and accessories as an ordinary thumbscrew can. Also supplied is a 1.25" eyepiece holder that slips into the 2" compression ring holder to let you use a 1.25" star diagonal or image erecting diagonal. Like the 2" eyepiece holder on the eyepiece holder rotation mechanism, the 1.25" adapter also uses a non-marring soft brass compression ring to hold 1.25" star diagonals and accessories in place.

Shipping/storage case: The AT92 comes standard in a 20.5"x9.5"x9" aluminum frame locking hard case with a carry handle for transportation and general protection purposes. 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.

Full Dimensions:  19" long with dew shield extended.  16" long with dew shield retracted.  Dew Shield diameter 4.75".  108mm tube diameter.  7.25 pounds.

Other supplied accessories: A slip-on metal dust cap is standard. As well as a set of hinged tube rings and a Vixen dovetail.

Tech Details

Aperture 92mm
Focal Length 506mm
Focal Ratio f/5.5
Heaviest Single Component 8 pounds
Optical Coatings Fully Multi-Coated
Telescope Type Refractor
Warranty 1 year


Review by:
I bought mine used, it's been a few years since there release but if you can find one don't pass it up, these scopes are awesome! I am mainly an imager due to living in bortle 7+ skies and this is the perfect scope for easy setup. I use an orion flattener (which looks to be the same as the Astro-tech) and have sharp stars edge to edge, some of the best HFR numbers I've seen with a scope (Under 2 with a 3 minute sub). The scope is not to heavy, but not to light, it feels quality and when collapsed is tiny, far shorter then a Stowaway and I'd say 95% of what a Stowaway can produce for FAR cheaper. The focuser is smooth and strong, has no issues with a ASI2600 and full filter wheel. I would wish they would come out again but if they don't look for a used one you can't go wrong. (Posted on 3/5/2023)
Review by:
I regretted selling my TMB92L some years ago. I purchased this AT92 as a replacement and I am very happy with it. I mounted this scope on my Sirius mount and started imaging. Images are just as good as my old TMB92. This scope has a better focuser which makes it even better than the TMB92. I recommend this scope. (Posted on 3/10/2021)
Review by:
I've been using this scope for astrophotography and I couldn't be happier! Lightweight, great optics, and can easily be handled by an Orion Sirius/HEQ5 Pro mount. The focuser is the best one I've owned. I think this is the ideal scope for the lighter weight mounts. (Posted on 4/24/2020)
Review by:
Finally, a clear night and enough time to get to my relatively dark observatory site and my two largest aperture scopes an hour and 45 minutes away. Seems like the first opportunity since last summer when I bought the AT-92 (the terrible weather alone should tell you how nice the scope is ;-). The plan is to first collimate my C-14 and troubleshoot the cantankerous controller on my Losmandy G11 but I am also planning to do some wide field observing with the AT-92. By the time the moon rises out of the trees 7 ½ hours later and puts paid to big faint fuzzies, I am an exhausted but happy camper after nothing but wide field observing. (OK maybe feeling a little guilty at neglecting the C-14). Even without the OIII filter I can see the Eastern, Western and Fleming’s Triangle parts of the Veil Nebula within the FOV of my 30 mm Explore Scientific 82° eyepiece. I share the view with a fellow observer and we later observe the Veil with his 16” Dob. It shows wonderful detail but requires panning around to even see all of the western portion, much less the other two parts. He allows that he really likes the more all-inclusive view in the AT-92. Moving on to the North American Nebula I can see both it and a “ghost” of the Pelican in the same FOV. The “Gulf of Mexico” is clearly a darker area. The view is even better with the OIII filter and I can still make out the belt stars of the Little Orion asterism, just west of the Gulf, with averted vision.
What did other common targets look like under 21 mpsas skies of above average transparency and poor to fair seeing ?

M8, Lagoon Nebula and Cluster – Using 30 mm e.p.: at 17x dark lanes in nebula and maybe 10 stars visible without the OIII filter and as Sagittarius was setting -- certainly not optimum conditions but a nice view
M20, Triffid Nebula and Cluster – In same FOV as Lagoon Nebula, very faint nebulosity and a few stars
M22, Globular Cluster – Using 17 mm Televue Nagler e.p.: at 30x no resolved stars just a fuzzy disk, brighter toward the center
M11, Wild Duck Cluster – Using 17 mm e.p.: A lead duck followed by a faint delta of mostly unresolved ducks, 3-4 stars resolved
M31 Andromeda Galaxy and Companions M32 and M110 – Nicely framed in FOV using 30 mm E.S. eyepiece. M31 extends across 3/5ths of the FOV. M32 is stellar at the 17x magnification
M33 Whirlpool Galaxy – Galaxy appears smaller than M31, again with 30 mm, but, although fainter, nucleus seems larger than that of M31 and somewhat off center to southeast
A few nights later, again at a dark site, I view M42 the Orion nebula with the AT-92 and a 6.7 mm E.S. 82-degree eyepiece yielding 76x. Three stars of Trapezium easily visible with the fourth winking in and out with averted vision. With this eyepiece the nebula is well framed in the FOV and takes on the appearance of a giant bird with M43 as the cocked head and bright star eye and a portion of the nebula extending back as a tail.
Earlier observations of the Moon, Jupiter, and Saturn from the middle of Houston with bright skies and above average seeing, showed crisp views without CA. At a magnification ~150x with the 6.7 mm eyepiece and 2X Orion Shorty Barlow four and maybe 5 belts were visible on Jupiter. Even with my 47-year-old 6 mm Jaegers Orthoscopic and barlow at ~170x four belts on Jupiter were clear as was one belt and the Cassini Division on Saturn.
All observations were made with the scope mounted on an Orion Tritech II Tripod, using a Desert Sky DSV-M head and a Rigel Quickfinder. The total grab-and-go weight of this setup is between 16-17 lbs if configured with a Baader Hyperion Zoom eyepiece, but a bit heavier with the big wide angles. This scope is an excellent all-arounder in a very portable package.
(Posted on 10/31/2019)
Review by:
I am very satisfied with this scope. I have it piggybacked on my Astrotech AT102ED for wide field and narrow field observation. (Posted on 10/24/2019)
Review by:
This is an outstanding APO. I use it as a dedicated astrophotography telescope, but it is great for visual observation and makes a great grab & go for travel or star parties. Images are crisp edge to edge. The focuser is smooth and everything is high quality. I doubt you could find a better APO refractor for this price, and it is worth paying for this quality rather than a lesser scope at lesser price. You do get what you pay for. This is my 3rd APO refractor, and my second scope from Astronomics. (Posted on 10/5/2019)
Review by:
I've owned a lot of small refractors. I love them for grab and go viewing, star parties and for the clarity they offer on the moon, star clusters and planets (within the limits of aperture). The AT92 is my favorite of all of the small refractors I've owned. Significantly better light gathering than an 80mm, more portable than a 100mm+ scope. Plus the TMB-designed optics are outstanding: Astronomics tells me that all the AT92's are 1/8 wave or better (0.95+ Strehl). The focuser and overall build is very solid and precise, even better than the AT80EDT. At f5.5, this needs a quality 2.5mm eyepiece for planetary work (it's quite capable of 60x/inch of aperture), and it also needs a field flattener for imaging. But at this aperture, the AT92 far exceeded my expectations and is an incredibly satisfying telescope. (Posted on 8/1/2019)
Review by:
I received my AT92 May 2, 2019 and had first light the following night. I am very impressed with how tiny this scope is and yet how capable. I viewed M42 low in the western sky. Beautiful with a 19 panoptic and AP Maxbright diagonal for 27x with an easily separated trapezium. I cranked up the power with a 8mm Ethos (63x), then added a 2.5x barlow (158x), then replaced the 8mm with a 3-6mm Nagler zoom and settled on the 4 level (316x). The stars remained tiny pinpoints with a first diffraction ring. I then viewed M51 which was very well positioned and showed as a dim puffball with stellar center but the clouds came in so I played around looking at some terrestrial sites at high power marveling at the crisp definition. This scope is a keeper. Very high contrast and much better definition than my 80mm triplet and so very close in performance to my excellent 102 Stellarvue but much smaller. Update July 22, 2019 - I did in fact sell my 80 and 102 scopes as redundant after having obtained the AT92. It is a do anything scope that has range from a 5.4 degree wide field of view to 316x on doubles and the moon. If the field curvature bothers you, there are ways to incorporate a field flattener and still use a diagonal and eyepieces. You can't ask for more from any scope of this aperture.

(Posted on 7/22/2019)
Review by:
I received the scope on January 17 2019. It arrived double boxed plus the black metal with chrome trim inside the two boxes. I t was well packed. I purchased it for mainly Astrophotography. Use it with the AT2FF . I have nice tight round stars to the edges of the subs. The focuser is very smooth and is able to hold my camera without any problem. The dew shield stays put even when the scope is pointed at the zenith with out the tension screw tightened!
The scope is light but substantial when you hold it. You can just feel the quality. The matte, almost like orange peel white finish along with the gun metal grey trim is luxurious. I would buy another one in a minute.
Clear skies and thanks for the great job Mike and the rest of the crew are Astronomics!
Mike from AZ (Posted on 3/21/2019)
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