Astro-Tech AT102ED 4" f/7 ED Refractor OTA


Availability: In stock

The Astro-Tech AT102ED is a fantastic value and incredible performer.
Our Product #: AT102ED
Astro-Tech Product #: AT102ED
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Product Description

This Astro-Tech AT102ED refractor has:

• 102mm f/7 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
• split tube rings with detachable Vixen-style dovetail for installation on virtually any mount

The AT102ED is bringing ED optics to you at a fantastic price. When this scope was available in 2008 the retail price was $995. The reintroduction not only has a much lower price, but it has better mechanics as well as advancements in the optical assembly and polish. You get a 2" Rack and Pinion focuser with a microfine 11:1 fine-focusing ratio finished in our Aston Martin Grey body. You get dual split mounting rings with a detachable 8" Vixen-style dovetail plate that lets you mount your AT102ED on virtually any altazimuth or German equatorial mount. The finely-machined Astro-Tech AT102ED 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.

For 2019 the 102ED has an improvement that has been asked for many, many times over.  The scope now comes with a retractable dew shield.

As with all Astro-Tech scopes, the AT102ED 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: 102mm (4") aperture, 714mm focal length, f/7 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 AT102ED 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.

• Internal light baffles: Three contrast-enhancing knife-edge internal light baffles and a specially darkened tube interior provide truly dark sky backgrounds and high terrestrial contrast. The edges of the lenses are blackened to reduce internal reflections and further improve image contrast.

• 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. The tube measures 28.5” long. 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 85mm (3.35") 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 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 durable high gloss automotive-grade white paint, the same as that used on scopes several times the price of the AT102ED. The focuser and trim are Aston Martin Grey anodized. The scope weighs 9.1 lbs with mounting rings attached.

• Tube rings and dovetail mounting plate: The 105mm o. d. body of the AT102ED comes with a pair of hinged split mounting rings and a detachable 8" long dovetail mounting plate. The dovetail plate fits directly into the head of many equatorial and altazimuth mounts. It will fit, without modification, Celestron Advanced Series and Meade LXD-75 go-to mounts; the Vixen Porta altazimuth mount; and Vixen Great Polaris and Sphinx mounts, among others. The longer length of the dovetail plate lets you balance the AT102ED more easily fore and aft in a mount’s dovetail slot. This lets you quickly accommodate changing balance conditions as you exchange an eyepiece for a camera, a 1.25" diagonal for a 2" diagonal, etc.

In addition, the dovetail plate can be unbolted from the split rings to allow you to mount the rings directly on other equatorial mounts – for example on the D-plate used on Losmandy mounts – something that is difficult to do with the short mounting foot on competitive clamshell rings. The dovetail plate also has a 1/4"-20 thread mounting hole that allows it to be installed on any suitable heavy-duty camera tripod that has a standard 1/4"-20 thread mounting bolt.

Tech Details

Aperture 102mm
Focal Length 714mm
Focal Ratio f/7
Heaviest Single Component 9 lbs.
Weight 8
Optical Coatings Multi-coated
Supplied Eyepiece None
Telescope Type Refractor
View Finder None
Warranty 1 year


Review by:
I purchased this in June, 2019 at $599.00. Pete provided excellent guidance and customer service. The scope, diagonal, and mount arrived and was easily assembled. Compared to my "other scope" (ETX90RA) this provides a deeper reach (about 1.5 mag) and much brighter, sharper images. I use it for DSO and occasionally for moon and planets. I am able to see GRS on Jupiter, which I was unable to view with ETX.

My primary passion are double stars. I was concerned about the "only 710" mm focal length but that has not been an issue. I have been able to routinely power up to 158x (9mm with 2x barlow) to split doubles. I am routinely in the 2.3" separation splitting zone.

I can see colors much better with this scope. The red of the Garnet Star exploded with color. Alberio is a pure joy.

The slo-mo controls are great to use and the Twilight 1 has provided a steady mount.

I use inexpensive Plossl eyepieces (Meade and the Astronomics) and am rewarded with wide FOV and sharp images.

Great scope at a wonderful price. Excellent value.

Ed (Posted on 8/7/2019)
Review by:
I had used to have Skywatcher ED80 back in the days and it had nightmare level of color aberration when watching through the bright object (e.g., moon). Now that I see many good reviews on this scope. I would like to test it with my triplets from TS Photoline. I'm pretty sure all the astrotech telescopes have exceptional build quality. And this obviously is a really good price for 100mm ED scope!. (Posted on 7/29/2019)
Review by:
I have the original version with the non-sliding dew shield. Very good mechanical and optical performance for the price. (Posted on 7/24/2019)
Review by:
I wanted to follow up my review. I got the scope out with good conditions and Jupiter high in the sky. The CA I saw and reported was simply not there once the scope was given a chance to cool down. I added a #8 Yellow filter for the moon and that completely rid the scope of CA even on the moon. Detail was beyond expectation. I saw 4 bands and the red spot with a 5mm Baader Hyperion. I am certain I also saw swirl detail. The air was remarkably still. Image size was about that of a marble so very reasonable. I ordered a barlow and will see if I can get this even better in size. There is no indication that the 5mm was pushing the scope. Just wanted to leave a better description of my experience. I was thinking of getting an APO...I got one as far as I am concerned. What a deal What a scope. Thank you! (Posted on 7/12/2019)
Review by:
Ok I was ready to face some CA when I got this given the price and glass. Yea it's there. BUT it's majorly slight so don't fret about it. It's only noticeable out of focus and then really really subtle on super bright objects.

Jupiter showed a tiny bit but it didn't affect the view.

Antares was perfect.

Vega was real close.

The moon was fine except as you suspect the rim has a really tiny purple line. No big deal.

Unlike other achromats the view isn't affected just that little thin color fringe. IF you really focus well it goes away. Hey built in focus finder! What made me title this is the view. The contrast and detail in the view are outrageous for the price. It's one hell of a scope. Ok people complained about the focuser. Fixed. The new one has to be made by starlight as it is the exact replacement one I bought for my C8. That was 300.00 by itself. Only wish would be it came with a case. Any case at all really. Buy it Now stop reading reviews.

Eyepiece makes a difference....just saying don't always blame the scope. (Posted on 7/2/2019)
Review by:
I was very hesitant to buy this scope. All of the reviews were excellent, but 599 is a lot of money. Then one day my inbox said it was on sale, but still I waited. I already had a 4" (Meade Infinity), would this really show anything different? When the website said only 3 left, I called Astronomic. I don't remember the gentleman's name I spoke with, but I was impressed that I didn't get a hard sell. I told him my concerns, and he agreed with most of my reasons why I shouldn't buy another 4". But he did point out that although the increase in the quality view MAY not have been worth the premium (it is :)), the build quality and longevity along with the images would be worth it. He was not wrong. It's a very solid piece of equipment, very smooth focuser and excellent finish. The views of Jupiter and Saturn through my Paradigms are excellent. Now my only problem is I need a better mount to compliment this excellent scope. (Posted on 1/14/2019)
Review by:
This my first refractor. Truly one of the best values out there. All of the guys in my club were impressed.
The the overall build and focuser are solid and the views are excellent. I plan to use this as an entry level imaging scope as well as a grab and go.
Yet another great Astro-Tech product! (Posted on 1/14/2019)
Review by:
Only 599 for 102 mm Apo ? I was skeptical then it came up for sale for 499. Well that's a no-brainer!
I have had my at102 side-by-side with several other 100 mm Apo doublets, all of which retail for much more, and the Astro Tech is equal to or better than the majority. False color is minimal even at high power on the moon. I'm not sure what magical coatings are used on the objective but looking at the reflection of a lamp in the optic produces almost no reflection whatsoever. This seems to give the Astro Tech an edge over some of my other 4" refractors in image brightness by allowing nearly all the Starlight to reach the eyepiece. My advice........get em while they last! (Posted on 1/10/2019)
Review by:
My friend lent me this telescope a few weeks back for me to use in Harmon IL as I was traveling there at first just to see the milky way since I cannot see it here in the suburbs of the city of Chicago. I paired this telescope with the Celestron AVX Equatorial mount for a quick and simple set up, and I began to image the Orion Nebula with my unmodified Nikon D5300 DLSR camera. After stacking 150 images of two minutes exposures, the photo came out very flat with no vignetting or anything. I would recommend though to get a focal reducer for this telescope if you are looking to image with this telescope so your images come out better. When looking into the visual use of this telescope, it is best to view in a somewhat "darker" place with not as much light pollution such as suburbs of the city of Chicago, etc. If you cannot travel to darker places then I would recommend getting a bigger telescope only if you are looking for visual purposes. Bigger telescopes are most of the time not great with DSO imaging. (Posted on 12/27/2018)
Review by:
Welcome back AT102ED! I have one of the original versions of this telescope when it sold for much more. I was impressed with the optical performance of the telescope then and was somewhat disappointed to see it disappear from the lineup not long after I got mine. Now years later I'm thrilled to see it back and available at an incredible price. This is a great grab and go telescope that provides good images, good color correction and is simple and easy to use. I also use mine as my solar scope using a Thousand Oaks optical solar filter on it. (Posted on 12/27/2018)
Review by:
I've had this for several months now and while I knew it was a good telescope I didn't realize how good until I was able to compare it side by side with a very high quality telescope.
The optical quality is good.
False color is barely noticeable in focus. Out of focus it quickly shows up.
The focuser is very good for a telescope in this price range. The other hardware is very nice, too.
Through the summer Mars always showed a polar cap and surface albedo features were visible through the dust storm. I preferred this to my C6 and C8 for observing Mars.
Cooldown is very quick. I have this on an alt-az mount in my front room able to be taken outside in one hand at a moment's notice.
I've used it for some astrophotography with a DSLR on an AVX and there is some bloat on stars but it isn't terribly objectionable.
It is a great value of a telescope. (Posted on 12/26/2018)
Review by:
This is a great little scope, and a great companion to my C8/AVX. The 102 sits on a manual GEM and works wonderfully for easily pulling out for shorter viewing sessions, or for lower magnification / wide field viewing. There is a slight bit of color on the lunar limb, but it is more that made up for by the quality glass figure and ED glass, which provides crisp detail for a 4" scope. Mechanics and construction are solid and function well. (Posted on 12/23/2018)
Review by:
This is a gem! If you are looking for a really good telescope that looks fantastic and gives great views this is the one. While not a triplet, CA is really well controlled, Views are as sharp as they can be and the focuser is among the best you can have embedded in an OTA.
Fit and finish are impressive. OTA feels solid, and 102mm is the ideal combination of portability and performance.
Do I recommend this OTA? Of course! hands down, one of the best telescopes you can have in your arsenal. (Posted on 12/11/2018)
Review by:
I am a relatively new astronomer and this is my second scope, I wanted a quick and easy setup with less dew issues for the warm summer months in my area (Florida.) This scope was recommended to me by the fine folks at Cloudy Nights and I cannot be happier with it. Beautiful crisp wide views, great sturdy build quality, nice smooth focuser, easy to adjust and customize to my needs. I bought the diagonal and finder from here as well, all excellent. Got a phone call from the fine people at Astronomics when my credit card company was not happy with my out-of-state charges, LOL, so the customer service was great. I am thoroughly enjoying my "grab and go" scope and would not hesitate to purchase an Astro-Tech scope again. (Posted on 12/10/2018)
Review by:
Up until a year ago, I owned a fpl-53 f/7 triplet that gave absolutely fantastic images. However, certain circumstances led me to sell it. Buyer's regret hit and I wanted to eventually replace it, but at a lesser cost. I had been following this scope for quite some time and actually ended up purchasing one second-hand online after resisting the sale price for several weeks. I had high expectations coming from a well built William Optics triplet and I must say that this scope has met those expectations. My only wish is that the dew shield could retract, but it's not a deal breaker. Easily splits doubles, and the contrast on planets is easily on par with other 4" triplets I've viewed through. Not quite flourite level, but still quite good. Chromatic aberration is visible on the limb of the moon and brighter stars, but it's not as much as I expected. There's more lateral aberration from my eyepieces than there is CA. Would definitely not hesitate to purchase again. Perfect for the visual observer who wants near color-free views without a high price tag. (Posted on 11/14/2018)
Review by:
I purchased this to use as a grab n go and a travel scope and it has exceeded my expectations. At first sight I was surprised what a beautifully made instrument it is. The paint finish is flawless and with the gray accents and the black and gold focuser it really has an understated elegance to it. I've had it out many times now and it performs as good as it looks. First and foremost, this thing puts up some razor sharp images! I've split stars at magnifications lower than I could ever use with my reflector. The E & F stars in the Trapezium were easy. Chromatic aberration is well controlled. It's not non existent but I would say very well controlled and only noticeable on very bright objects. The focuser is well made, precise and smooth. I have pushed this scope to some fairly high magnifications like 260x and the 2 speed focuser makes focusing easy. It's just a great all around scope and an over achiever at this price point. It has just enough aperture to show a variety of objects well. It's great on planets and open clusters sparkle like diamonds. I've viewed everything from the brighter galaxies to small planetary nebula and it continues to impress me. Then there's the wide field views. Wow! Nice contrast and crisp stars across the field. It's just a very versatile telescope that I look forward to using for many years to come. Thanks Astronomics! This ones a winner for sure. (Posted on 11/6/2018)
Review by:
Hi folks.
This is my second refractor, and my first ED scope. I bought this as an upgrade from my four inch Celestron achromat, and I’m sure glad I did! The AT102ED is an amazing scope! At first sight I could tell the mechanical quality is much better, the paint job looks great and the focuser is strong and smooth. The color correction is Miles ahead of the achromat, and it was obvious viewing Jupiter that the color error is very small compared to the achro. I think to get a better mechanical/ color corrected scope you're looking at $2000 and up, and that makes the AT102ED a veritable bargain. (Posted on 11/4/2018)
Review by:
The AT102ED represents an amazing bargain for a 4" class ED doublet. The overall build quality is superb. The telescope is extremely well baffled (4 baffles in the main tube and 12 in the focuser drawtube), has excellent coatings, and a robust 2.5" focuser. Spherical correction on my sample is very good. Color correction is quite good but the scope will show faint violet on bright targets at high power (Vega for example). The lens also seems to have a very nice polish as overall scatter control is excellent and on par with a pricier Japanese manufactured scope I also own. From sharp, high power views to low power sweeping, I don't know of any other telescope at this price that can do it all so well. (Posted on 11/1/2018)
Review by:
Just finished up a lunar session with my AT102ED, under the best seeing conditions I've experienced in years. The rays of Aristillus, catching sunlight at a very low angle, clearly show that they are in fact, ridges. And tall ones at that. Just one of many memorable images I've seen with this 4" refractor over the last nine months.

This is scope has given me the best return on investment of any astro-equipment I've ever purchased. For $599 I have a light weight, well constructed 4" refractor with ED glass and focuser that doesn't have to take back seat to any scope costing twice as much - or more. Coupled with a Voyager II alt-az mount, it is easily picked up (28 pounds) and carried outside on a moment's notice. A couple older TeleVue eyepieces and barlow lens live in the tripod spreader, so everything is right there in just a single trip. (A second trip brings the equally important observing chair and adult beverage.)

From richest-field capability (nearly 3 1/2 degree true field of view), to high powered viewing at 200x and everything in between - this is without a doubt, the most versatile telescope you can buy for the money. (Posted on 10/16/2018)
Review by:
I purchased this telescope when it was on sale for $499 = I thought it was a steal. The build quality is excellent, including the focuser. I've done some color (moon) and monochrome imaging and have been pleased with the results. (Posted on 10/7/2018)
Review by:
I've had the 2018 version for several months now. Very impressed with the optics and build quality and it looks great. The focuser is great - very smooth - and I really appreciate the 3 tension screws vs. 2. Optics are even better than I expected with some slight color on a few objects but mostly very hard to see. A keeper for me. (Posted on 10/7/2018)
Review by:
I grabbed one of these during the sale also and have been quite impressed with the cost to performance. It is much better than the achromats here but is not an apochromat but it is much closer to an apochromat than an achromat. The optics are better than I expected and so is the focuser even though there is some focus shift. All in all I've been having fun with it and wish Astronomics would make this in a 127mm. That extra inch helps with my right eye. (Posted on 10/7/2018)
Review by:
I have used this scope for several months now and have been extremely pleased with its performance. Cullimation is spot on and it handles magnification very well. Views of the gas giants exhibited a surprising amount of detail with the limiting factor being the Missouri skies. Deep sky objects exhibited good contrast and resolving brighter globulars was only limited by the 4 inch aperture. Fit, finish and mechanics are far above the modest sale price of $499. (Posted on 10/6/2018)
Review by:
I purchased this scope several months back during the $499 sale. This scope has been one one of the most pleasant surprises of any of my scope purchases. For the price, it exudes quality construction and is buttoned down nicely. The replacement focuser - the original was damaged due shipment - is silky smooth with a wonderful feel. Best of all are the optics! The optics on this scope are very good - bright contrasty views and it takes high magnification well.

Highly recommended! (Posted on 10/6/2018)
Review by:
I got this when the 1st batch arrived and I'm really glad I did. Excellent images with little if any color. I think that the small amount of color I saw on the Moon's limb might have been from the eyepiece I was using. On an expensive triplet I bought from another well known brand, I had to replace the focuser due to it's poor performance. Not so on the AT102ED. The stock focuser is surprisingly well built. Definitely a keeper. (Posted on 10/6/2018)
Review by:
I've had this scope for four months now and have been loving it. I bought it as a grab and go / public outreach scope. It gives great views of the moon and planets at public events. Nothing better than a child's face the first time they see Saturn. Binary stars that I've been able to view (very rainy summer) have resolved nicely.I do get veeerryy slight fringing on the moon at high magnification (+200X) but it something you have to look for, it isn't generally noticeable.

All hardware is beautifully finished and performs well. Focuser is smooth for both fast and fine adjustment.

All and all a great scope that outperforms it's price.
(Posted on 10/6/2018)
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