Telescope Reviews: New Celestron Ultima DX 10X50 impression

First light this past Thursday night. This is not a very technical report on them as I do not have any truly accurate tools to measure with other than a metric ruler, but I have studied the concepts of what specifications mean as applied to binoculars extensively. I'm no professor, but no dummy.

First of all, the construction feels sturdy enough. I believe they would hold up in the field. Friction is nice and stiff for iinterpupillary adjustment (the way I like it, at least). They seem to hold their position well. Also, diopter adjustment is stiff, almost too stiff for me, especially for use with the thin, almost sharp (due to the stiffness) tabs that protrude from the adjuster. Focusing is smooth with a proper resistance, but herein lies my first fault with these binoculars, namely an undue amount of play in the mechanism. This is most annoying to me, making it difficult to reach optimmum focus when changing directions. I have overcome this by usually trying to reach optimum from one direction only. But this should not be necessary, of course.

Image quality is stunning to me as compared to what I have been using. I cannot compare these to higher quality binoculars since I do not have experience enough. But to those who are looking to upgrade from cheap optics and coatings I would recommend these, based solely on image quality. And the price is moderate. (I found these for one-third the list price).

Exit pupil appears to be 5mm, and aperature 50mm. I cannot speak for effective aperature or magnification.

Eye relief is too much. This is my single-most gripe with these binoculars. I wear eyeglasses, moderately thick ones, so the listed 19mm seemed to fit. I further thought that the listed specs may not live up to this (as in not accounting for the distance from the edge af the eyecup to the lens itself). I may have gotten the full 19mm from the eyecup to my eye, it seems. Whatever the number, the kidney bean/blackout effect is present. I must hold my eyes in a restricted area to reduce this effect with the eyecups fully down. Better viewing is found with the eyecups twisted up two to three mm inorder to still see the full field of view (or 90%). The effect is less distracting the further the eyecups are twisted out. Of course the field of view becomes less.

Apparent field of view should theoretically be about 65 degrees, and this appears to be the case when roughly viewing Orion's belt. I know this is not accurate, but it "feels" right.

The twist-up eyecups work well, although they are not click-stop (except at fully closed and fully open). That's ok. Theystay where I put them, but I must think about how far each one is in order for them to be equal. That's ok,too, since they are infinitel adjustable between stops.

So, overall, actually a very nice pair. They are a little bulky, not bad. For me it's the blackout that bothers me most.

I'm sure someone else could do a better job of reporting than I, but I just wanted to give my two-cents.

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--Russell

"Akita mani yo." Observe everything as you walk. (--Lakota)

Celestron Celestar 8 Standard SCT, f10
Celestron 80mm Wide View ref., f5
Criterion RV-6 Dynascope, Newt., f8, (c. 1962)
Sears Discoverer 60mm ref., f7, (c. 1973)
Celestron Ultima DX 10x50, 6.5 TFOV
Tasco 7x35 wide
Several mediocre eyepieces

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