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Astro-Tech AT125EDL Refractor OTA FCD-100 and Lanthanum f/7.8 Doublet

Regular Price: $1,849.00

Special Price $1,695.00

Availability: In stock

The Astro-Tech AT125EDL takes the performance of the it smaller siblings and combines it with the mechanics of the EDT line.
Our Product #: AT125EDL
Astro-Tech Product #: AT125EDL
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Product Description

This Astro-Tech ED refractor has:
• 125mm f/7.8 fully multicoated FCD-100ED and Lanthanum doublet refractor optics
• dual-speed 2.5" Rack and Pinion 2” focuser with 10:1 ratio fine focusing (Same mechanism as our EDT series)
• 2” and 1.25” non-marring compression ring accessory holders
• Vixen dovetail plate with two tube rings and a carry handle
• retractable self-storing lens shade
• .95 Strehl ratio minimum
• long-lasting white finish with Aston Martin Grey focuser and trim

The new Astro-Tech AT125EDL is an extension of the beloved 60ED and 72EDII. This scope is the ultimate doublet refractor for those not wanting the weight and cool down of a triplet optical set.

The important perfomance updates come in the type of ED element combination and the type of foucser the AT125EDL is built around. The new AT125EDL has upgraded the ED element to FCD-100 with a Lathanum mating element. Our first star test on the AT72EDII prototype was simply textbook. A perfectly defined set of white diffraction rings with jet black spacing. As this is an extension of that philosophy I know the AT125EDL will preform just as well. The next upgrade comes with the 2.5" Rack and Pinion focuser with 10:1 fine focus knob. It is the same mechanism as our EDT line and is buttery smooth. The focuser also comes with a built in Camera Angle Adjuster to help you get just the right position for your camera or diagonal. The final upgrade is something that people have asked us about for years...a simple carry handle. The ergonomic handle mounted on the top of the tube rings will make setting up a breeze.

This 33.5” long refractor optical tube could be all the refractor you will ever need. Its combination of aperture, glass type, and build allows the scope to be a fantastic visual instrument as well as a great photographic instrument. A good 5" refractor can give you the views of the night sky you have always dreamed about. The supplied Vixen style dovetail fits directly into the dovetail slot on the top of many altazimuth and German equatorial mounts, such as those from Astro-Tech, Celestron, Meade, and Vixen.  The OTA weighs in at 16 pounds with rings and dovetail.

Features of this Telescope . . .

AT125EDL doublet refractor optics: 125mm (5”) aperture, 975mm focal length, f/7.8 focal ratio air-spaced doublet lens using premium FCD-100 ED (Extra-low Dispersion glass) with a Lanthanum mating element to reduce spurious color halos and fringing to vanishingly low levels with a .95 strehl ratio minimum guarantee. While we do not claim fully apochromatic performance in the class of a multiple thousand dollar Takahashi (this instrument is a sort of homage to the FS series), Astro-Physics, or TMB refractor, the AT125EDL 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 multiple contrast-enhancing knife edge baffles inside the optical tube, and Micro Baffles running the full length of the focuser drawtube, 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.

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 dew shield is 170mm in diameter.

Dual speed microfine 2.5” Rack and Pinion focuser with 1.25” adapter: 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 10:1 ratio reduction gear microfine focusing. This provides exceptionally precise image control during high power visual observing or critical DSLR or CCD imaging. The focus knobs have knurled gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather. The 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 2” compression ring accessory holder to accept a 2” star diagonal and 2” photo accessories.

The supplied 1.25” accessory adapter slips onto the 2” accessory holder and uses a soft brass compression ring to hold 1.25” star diagonals and photo/visual accessories in place. The 1.25” and 2” compression rings won’t scratch the barrels of your star diagonal or accessories as an ordinary thumbscrew can.

Tube finish: The optical tube is finished in a white powder coat with Aston Martin Grey metal pieces.

Other supplied accessories: A slip-on metal dust cap is standard, as well as the CNC carry handle. Two threaded holes for installing a finderscope mounting bracket are located on the upper left and upper right side of the scope body.

Tech Details

Aperture 125mm
Focal Length 975mm
Focal Ratio f/7.8
Heaviest Single Component 16 pounds
Optical Coatings Fully Multi-Coated
Telescope Type Refractor
Warranty 1 year
Back Focus 150mm


Review by:
I received my AT125EDL a few weeks ago and have had fantastic views with it. The aperture provides much more light capture than my previous scope, resulting in brighter and sharper images with much more resolution. The fit and finish is wonderful....from the powder-coated white finish on the OTA to the grey color on the focuser. The rack and pinion focuser is smooth and more worrying about loading up heavy eyepieces. The rotating focuser is a bonus I hadn't expected. I am purely visual and the first time out with this scope, I couldn't believe what I was seeing and for a moment, forgot I was using my new telescope, rather than my old one. Thus, I didn't stretch my imagination to believe the new scope was was. I am 73 years old and not the strongest guy in my age group. I had worried about the weight but have found that it is no problem, especially with the provided handle, to load this up on my mount and take it down. In fact, I don't find it any more difficult to deal with than my previous 4" refractor which weighed half as much. This 5" scope will be my forever refractor! (Posted on 2/15/2022)
Review by:
Starging off in astrophotography with a Nikon D850 & Sigma 150-600mm zoom on a Star Adventurer Pro tracker, I reluctantly gave up the reach of the zoom in favor of sharper optics & cleaner stars from a 360mm W.O. Zenithstar 61II which is a terrific lens but I clamored for more. Upgrading my mount to an iOptron CEM40 and also moving from a DSLR to an OSC astro camera with the ZWO ASI6200MC, the weight of the AT125EDL seemed optimum for the mount and the 975mm focal length was an ideal match for the camera. However, being a full-frame camera, I had to sacrifice some reach to obtain a flatter field with sharper stars toward the perimeter, and thus I also bought the 0.8X reducer/flattener. That works great, but I had to taste the 975mm reach, so I shot sans flattener and found I was able to utilize 75% of the full-frame image with star quality quite acceptable vs. the usable area, that being in contrast to a 55% smaller coverage from an APS-C sensor relative to full-frame. So, I can only report that I'm very happy with the imaging performance of this telescope and having bought a right-angle finder and pair of eyepieces, I also look forward to having my first quality telescope for visual astronomy as well. The build quality overall is excellent and the only thing I might quibble with is that I wish the screws for the focusing rail and field rotator would actually lock down the movement, but they are more just to increase the friction...I saw the same as true with my Z61II, so I guess that is the typical direction manufacturers go. Finally, as noted in my review summary, I chose to continue using my ZWO Mini guide scope and ASI120MM-S camera as my autoguider for this telescope, at least until I learned if they would be enough. And in fact, they are...with my ASIAir Plus as the guiding/imaging controller under Bortle 5 skies, I'm seeing a total tracking error that usually is around the 0.6-0.7" range, which seems very good to me. (Posted on 2/9/2022)
Review by:
Let me start by saying that I cancelled 2 orders during this covid delay. So I'm somewhat of a high maintenance if not impulsive customer. Never had a problem getting someone on the phone however.
Ordered this scope based on memories of the sharp views obtained with Skywatchers 120ed f7.5. I was not disappointed. This scope throws up extremely sharp views and inky dark skies as did the Skywatcher but with better color correction. Of course the mechanicals are on another level and the tube is built like a tank. Great product.
Thanks (Posted on 10/31/2021)
Review by:
I have had my AT125 for almost 3 months now. I have had it out numerous times for visual and CMOS imaging. I have always wanted a 5" Class apochromatic refractor but didn't want to compromise to get there. The AT125EDL is not a compromise. Weather I am observing at 420x on the planets, mid to high power deep sky observing, wide field deep sky observing or imaging, the scope is sharp, no false color and snaps to focus. Optics are as good as I have ever seen in ANY refractor. Mechanically, the scope is outstanding as well. Very nice tube rings, a beautiful powder coat finish and the focuser is outstanding for both visual and photographic uses. I realy like that the tube rings have tapped holes on the sides as well as this allowed me to move the finder to my much perferred location and not on the focuser. I have not found one thing I don't like about this scope and I see it riding on my CGEM permanetly moving forward for observing, public observing and astrophotography. Thanks Astro-Tech and Astronomics for bringing another outstanding product to this hobby at a great price. Highly recommended! (Posted on 8/9/2021)
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