Astro-Tech AT70ED 2.8" f/6 ED Refractor OTA

$299.00

Availability: More on the way

The Astro-Tech AT70ED could be the perfect grab and go refractor.
Our Product #: AT70ED
Astro-Tech Product #: AT70ED
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Product Description

January 2021 Expected Delivery

This Astro-Tech AT70ED refractor has:

• 70mm f/6 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
• Single ring with a foot that has a 1/4" 20 thread hole for easy attachment to a dovetail.

Length:  11.8" dewshield retracted

Weight:  4lbs 13.6 oz with the ring

The AT70ED is bringing ED optics to you at a fantastic price. You get a 2" Rack and Pinion focuser with a microfine 11:1 fine-focusing ratio finished in our Aston Martin Grey trim. You get a single ring with a built in foot.  The foot has a 1/4" 20 thread hole for easy attachment to a photo tripod or a dovetail of your choice. The finely-machined Astro-Tech AT70ED 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.  The AT70ED also comes with a retractable dew shield to make it as compact as possible at a tad under one foot.

As with all Astro-Tech scopes, the AT70ED 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: 70mm (2.8") aperture, 420mm focal length, f/6 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 AT70ED 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.

• 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.  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 81mm (3.15") 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 optional 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 automotive-grade white paint, the same as that used on scopes several times the price of the AT70ED. The focuser and trim are Aston Martin Grey anodized. 

Tech Details

Aperture 70mm
Focal Length 420mm
Focal Ratio f/6
Heaviest Single Component 4 lbs 13 ounces
Optical Coatings Multi-coated
Supplied Eyepiece None
Telescope Type Refractor
View Finder None
Warranty 1 year

Reviews

Review by:
Astro-Tech AT-70ED OTA 06/24/2021

I just got my new AT-70ED ($299.00)from Astronomics today. My intention was to use my Nexstar 6SE GOTO mount and tripod to mount the OTA and start doing some simple astro photography with it. To this end, I have also ordered a ZWO ASI224CS camera for it. My main intention for the scope is AP or EAA and not much visual astronomy use since it is a small aperture scope.
The scope arrived on time from FEDEX Home Delivery in excellent shape. I ship a lot of heavy and pricey items so I was impressed to see the little scope was triple boxed. Great Job Astronomics! I opened the boxes to get a look at it and discovered that it looked exactly like in the online store photos...no surprises there.
I took the scope out and attempted to mount it to the Nexstar 6SE mount I have but it would not seat and tighten up properly in the dovetail clamp. A little visual checking and I decided to attempt to attach the original OTA bracket to a heavy 8” dovetail I had laying around. At first I used the 1/4-20 bolts I had which were hex head. It bolted up fine but the hex heads caused interference in the mount clamp so I decided to get a set of 1/4-20 Allen wrench bolts with smaller and rounded heads. These use a 5/32 Allen wrench to tighten. This solved the problem right away and now the OTA clamps right up to the Nexstar mount without any problems.
Once I got the OTA mounted, I also added a 6x30 finder scope to the accy bracket provided on the top of the OTA. I went outside and set the scope up for a test and align the finder. I popped in a 20mm WA eyepiece and removed all the OTA and finder scope caps so I could see thru it. I focused in on a bird house out in my side yard and I was happily impressed with the view. It was the clearest view I have ever had of that bird house from my drive way. I have had all kinds of scopes here mostly CATS and NEWTS but none of them produced a tack sharp view as well as this little 70ED. Then I tried my Celestron 8-24 Zoom eyepiece to see how well the image held up under more power. It remained sharp all the way up to the 8mm setting, albeit somewhat dimmer. I should say, I am not a refractor person. That is I have had some APO’s before 80 and 100mm, but just for a very short time. I never gave them a chance to satisfy me. They just seemed too small to be of any visual use to me. But now, since my plans are for mostly AP, I can see how this will fit in my routine such as it is and provide some quick grab and go visual use also. As a matter of fact, I may save up and get the AT-102ED version in the future. I will also probably have to get a heavier mount probably a GOTO GEM in the future also. Time will tell if all this takes place or not. Will attempt to use it out at night ASAP especially when the camera arrives.
All in all, seems like a very nice OTA for the money. Time will tell.
Tom H (Posted on 6/24/2021)
Review by:
Astro-Tech AT-70ED OTA 06/24/2021


I just got my new AT-70ED ($299.00)from Astronomics today. My intention was to use my Nexstar 6SE GOTO mount and tripod to mount the OTA and start doing some simple astro photography with it. To this end, I have also ordered a ZWO ASI224CS camera for it. My main intention for the scope is AP or EAA and not much visual astronomy use since it is a small aperture scope.
The scope arrived on time from FEDEX Home Delivery in excellent shape. I ship a lot of heavy and pricey items so I was impressed to see the little scope was triple boxed. Great Job Astronomics! I opened the boxes to get a look at it and discovered that it looked exactly like in the online store photos...no surprises there.
I took the scope out and attempted to mount it to the Nexstar 6SE mount I have but it would not seat and tighten up properly in the dovetail clamp. A little visual checking and I decided to attempt to attach the original OTA bracket to a heavy 8” dovetail I had laying around. At first I used the 1/4-20 bolts I had which were hex head. It bolted up fine but the hex heads caused interference in the mount clamp so I decided to get a set of 1/4-20 Allen wrench bolts with smaller and rounded heads. These use a 5/32 Allen wrench to tighten. This solved the problem right away and now the OTA clamps right up to the Nexstar mount without any problems.
Once I got the OTA mounted, I also added a 6x30 finder scope to the accy bracket provided on the top of the OTA. I went outside and set the scope up for a test and align the finder. I popped in a 20mm WA eyepiece and removed all the OTA and finder scope caps so I could see thru it. I focused in on a bird house out in my side yard and I was happily impressed with the view. It was the clearest view I have ever had of that bird house from my drive way. I have had all kinds of scopes here mostly CATS and NEWTS but none of them produced a tack sharp view as well as this little 70ED. Then I tried my Celestron 8-24 Zoom eyepiece to see how well the image held up under more power. It remained sharp all the way up to the 8mm setting, albeit somewhat dimmer. I should say, I am not a refractor person. That is I have had some APO’s before 80 and 100mm, but just for a very short time. I never gave them a chance to satisfy me. They just seemed too small to be of any visual use to me. But now, since my plans are for mostly AP, I can see how this will fit in my routine such as it is and provide some quick grab and go visual use also. As a matter of fact, I may save up and get the AT-102ED version in the future. I will also probably have to get a heavier mount probably a GOTO GEM in the future also. Time will tell if all this takes place or not. Will attempt to use it out at night ASAP especially when the camera arrives.
All in all, seems like a very nice OTA for the money. Time will tell. (Posted on 6/24/2021)
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