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Customer Comments

Here’s what a few OA-Series™ owners have to say:

What a scope!!!!!!!!! I will sell ALL of my GoTo gizmos Mak-Newts... THIS IS THE BEST SCOPE I'VE EVER LOOKED THROUGH. PERIOD! I thought I had a perfect optics in my 1980 vintage Questar (and I still think it is) but after having had a look at the moon and the gas giants last night, knocked me of my chair (collimation was a breeeeeeze)! I ended up spending A LOT more time behind the eyepiece then I had accounted for. Hmm, after a couple of hours my spouse began to look worried. Dan, this scope is a keeper. It doesn't matter whatever "Computerized, GoTo, GPS, exotic optics" jargon they will throw at me. I will NEVER part with my OA-4. "Now let me see, if I get rid of that and that I could get me one of those OA-9s..." :-)

P.L. Torpet, Sweden, OA-4.0 owner

I am getting better at aligning the optics and the views of the planets are breathtaking. Saturn rocks. Using a homemade 20mm plossl I saw Tethys without using averted vision during a full moon, I could make out a lot of detail on Saturn’s disc, the Cassini division, Titan really bright, Iapetus with averted vision, and Rhea with Dione off and on along with a ninth magnitude star very close by. Really didn’t know this was possible with a 4” scope under moonlit suburban skies at only 50x.

S.W. Tahlequah, OK OA-4.0 owner

Just a quick note to let you know how well my first 2 (clear!) nights went with the new OA-4...

Fit and finish: outstanding! Edmund Red looks great. Helical focuser is really nice. I think I like it's precision better than R & P focusers. Motions/friction: outstanding! I've read about LP records on Dobs, I had no idea they worked better than Ebony Star. But, it sure does! Friction adjustment works really well. I may want one for the other side, not for the friction, but for added security when carrying the OTA and base simultaneously...

Engineering: Outstanding! Split yoke is a pleasure to use. Great latch! Mirror cell works great, collimates smoothly. Amused to see Duct tape holding the mirror on. So that's how professionals do it, eh? Knowing this works will make my future ATM 'scopes a little easier to build. Collimation: easy, with a bit of practice, and cooled mirror for the star test portion.

Optics: Absolutely flawless, to me. So that's what the star test is supposed to show, eh? Never seen diffraction rings the same on both sides, on any 'scope (I always check this out when someone is showing me something through their 'scope). I can't see the zonal error you told me about. Sharp! Sharp! Sharp! Best detail I've had on Jupiter through any 'scope. I've never seen detail inside the Great Read Spot before. Alnitak was a truly beautiful split with black space between the components, and a beautiful yellow/green to the b star, under less than ideal seeing, too. 70x/inch was pretty easy, even on Jupiter, again, under less than perfect seeing. Impressive. And, the views of open clusters with my 32mm Plossl were stunning becasue of the tiny points of light the stars formed. I think there will be a larger aperture OA 'scope for me in the future.

--KR, Kalamazoo, MI, OA-4.0 owner


Hi Dan, I love the skies this time of year.  It's a very still night tonight, atmospherically speaking, and I'm getting some nice views out there with the OA-4.0. On Saturn, the Cassini Division and Crepe Ring really stand out, as well as a few moons.  Jupiter is not as high in the sky yet, but the banding  looks nice and the moons look like moons. Betelgeuse is fiery red-orange, Rigel is blue and it's companion is easily in view. The Trapezium is nice and sharp, and the Orion Nebula looks great too.  As always, the star test looks perfect.  I really haven't had to fiddle with the collimation once I got it right; it seems to hold pretty well. I usually do a quick star test to start off and as long as there's no astigmatism, I don't mess around. Funny thing; there seems to be less heat distortion when it's cold out. During the summer it seemed present all the time. Perhaps it's that the air is more still this time of year; sometimes it's hard to tell the difference between the effects of heat waves and atmospheric turbulence. Anyway, the scope is really throwing up some nice views of the gas giants and I just wanted to let you know I'm still enjoying it very much. The best planetary views seem to be between about 100 and 200 mags. I don't have the eyepieces to go farther yet, but my guess is that I could probably go up to 250 on good nights with good quality eyepieces before image breakdown. This means the scope can comfortably handle 50 to 60 mags per inch of aperture which is
pretty good when you think about it. The images are not quite as bright as with my old 6 inch refractor, but they're pretty close.  That's also extraordinary for 4 inches of aperture. Add to that zero false color and I think we have a winner here.

--TC, Cheshire, CT, OA-4.0 owner 


Finally have some good seeing here in FL & have had several months to evaluate your scope & get the collimation in, or at least close. I was amazed to see dark brown color on one Jupiters bands using your 4". I didn't think this was possible with a 4" scope but, I've seen it 2 nights in a row now. This is using a 12mm eyepiece. For some reason, I don't feel the need to push the power with this scope. I can't figure it out: a 12mm looks like 125X in other scopes for some reason? Anyway, I'd have to be hard up to sell this scope as it's easily the best 4" I've ever looked through. Images are sharp & contrasty.

 --JY, Spring Hill FL, OA-4.0 owner

“I was out the other night, Dan, with my OA, and though the night was far from perfect (high level haze), I am always amazed at the view from your scope. Whoever does your mirrors must work for the space program — they are perfect! I looked at the crescent moon, and could see the tiniest stars directly adjacent, with absolutely perfect images (except for some astigmatism in my right eye!). My left eye is better.  The other thing I really like about your scope, Dan, is its ergonomics. Setting up and using your scope, usually while seated on a comfortable observing chair, is so much more pleasant than struggling with a tripod, some GOTO system, refractor OTA, etc. I am a fan of medium-sized scopes, and your scope really delivers! The only drawback I can think of, is the larger size of the OTA, but when you factor in unwieldy tripods, yours is the clear winner!"

--M.M., Waterloo, Iowa, OA-5.1 ATS owner

 “I watched part of a shadow transit last night and shadow looked so black that it appeared a hole had been drilled into Jupiter. The two Equatorial Bands looked like two meandering rivers! I could see small ovals of light and dark material inside the bands. Actually it's near impossible to describe in words, what I was seeing there was so much detail.”

--M.T., Corpus Christi, TX, OA-5.5 owner

“The 5.5 has performed brilliantly the last several times out, including an incredible view of Jupiter, with bands and festoons. The new crescent Moon was spectacular at magnifications up to 220 power, with steady seeing.”

--C.C., Concord, NH, OA-5.5 owner

“Perfect star images. I thought I had good optics with my 8" Newtonian.  I didn’t know what good optics were like.”

--R.P., Niagra Falls, NY, OA-4 owner

“Very crisp and clear images.  Went together very easily after unpacking.”

--K.K., Kasai Trading, Toyko, Japan, OA-4 & OA-5.5 ordered

The finest optical images I’ve seen with any scope.”

--S.L., Lawrence, KS, OA-4 owner

"No comparison with the 8 inch scope I borrowed from my club. M13 split into many stars even from my light polluted location.”

--B.T., Albany, NY, OA-7 owner