Celestron Ultima 10×50 Binoculars

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The bridge of the Celestron Ultima 10×50 binoculars has a 1/4-20 socket for attaching to a tripod with an optional adapter. The lenses are well-coated, presenting dark reflections. Credit: Alan Dyer

Celestron’s Ultima-branded binoculars are back, with a new pair of 10x50s at an entry-level price.

Plus: Sharp on-axis images; no ghosting or flares; light weight

Minus: Roll-down (not twist-down) eyecups; off-axis images soft; narrow focus wheel

Summary: Celestron’s new 10×50 Ultimas are classic Porro prism binoculars, with excellent eye relief and coatings in a lightweight housing. 

Who Is It For? Young astronomers, and beginners of any age, looking for a quality astronomy binocular at an affordable price. 

Celestron has always had strong lines of binoculars in their catalog with, not surprisingly, many models aimed at astronomers. Years ago Celestron attached the “Ultima” name to many of their binoculars. I still have a pair of Ultima 8x56s from long ago.

The Ultima line is back, with new 8×32, 8×42 and 10×42 Porro prism binoculars. However, it is the new 10×50 Ultima that will be best suited for astronomy, with its generous 50mm aperture and 10x magnification good for resolving star clusters and picking out galaxies (yes, some can be seen in binoculars).

I tested an early production sample sent by Celestron for review. In fact, as I write this in early 2021, most dealers have yet to receive their supplies of the new Ultima series. 

Classic Design

The 10×50 Ultima is a classic Porro prism design that resembles binoculars from years past. As such, the focus wheel is narrow and placed toward the back. By comparison, other Porros I’ve tested have a wider focus wheel more centrally positioned where it can be easier to reach and turn, especially with gloves on.

However, the Ultima’s body is smaller than many other Porros, so reaching the focus wheel is easier, especially with smaller hands. The focus wheel is also rubberized, not hard metal, for a secure, non-slip contact. In sub-freezing temperatures the focuser’s grease did stiffen up, but it was still usable. 

The eyepiece bridge is wobble-free. The right eyepiece has a smooth but firm diopter adjustment. The eyecups roll up and down, but can be uncomfortably narrow. Credit: Alan Dyer

The eyepiece bridge is sturdy and doesn’t rock up and down, as it can on some Porro prism binoculars, compromising focus. The binoculars can be squeezed down to an interpupillary distance of only 52mm, unusually close, another good feature for use by children.

The right-eye diopter adjustment is smooth but firm, so once set to accommodate a user’s eyes it won’t turn by accident, throwing that eyepiece out of focus. 

As is the case for most lower-cost Porro binoculars, the prisms in the Ultimas appear to be glued in place, not held in metal cages. They’ll work fine; just don’t drop them!  

The body is said to be aluminum in construction, but is covered in a soft rubber-like finish, making the binoculars easy to grip firmly. They are certainly a pleasure to hold, especially with their light 790 gram (28 ounce) weight, making them the lightest of all the dozen or so 50mm binoculars, Porro and roof prism, I’ve testing in recent months. Most 50mm models tip the scales at 850 to 1000 grams. The Ultima’s light weight will make for less tired arms during an evening of stargazing. 

The Ultimas are promised to be dry nitrogen-filled and waterproof, but I’m always reluctant to put such a claim to the test. All Porro prism models with external central focusing are difficult to make fully waterproof, so I suggest not leaving your binoculars out in the rain or dunking them in the lake!

In all, while the Ultima’s design is classic, even a bit “old-fashioned,” it is well executed with notable improvements over binoculars of old, such as the grippy finish and focus wheel.

One feature that is still “old-school” is the eye cups. While they are soft, they are narrow and tend to be uncomfortable against the eye sockets. To use the binoculars with eyeglasses, you have to roll the eyecups down, a fiddly process. They tend to pop back up easily. And all roll-down eyecups are susceptible to drying out and cracking over long term use. I would have preferred the twist-up style of wider eyecups that many binoculars, even low-cost models, now feature. 

Ultima Optics

Where the Ultimas do stand out over older Porro prism models, and even some current ones, is their long eye relief. At a measured 15mm from the top of the rolled-down eyecups, it is generous enough for comfortable eyeglass use. Years ago we had to pay a premium price for such “high-eyepoint” binoculars. 

The coatings are also excellent, with all lenses multi-coated. When looking at the Moon and bright light sources, I saw no ghost images or lens flares across the field. Only with the Moon just outside the field was there some glare visible spilling into the eyepiece, true of most binoculars. 

With an apparent field of 60° and an actual field of 6°, the Ultima’s field of view is wider than in many low-priced Porro prism binoculars, certainly older models, which typically might have apparent fields of only 50°. However, higher-end models, both Porro and roof prism designs, can have apparent fields of 65° for an even more immersive view.

Star images were sharp at the center of the field with little sign of image-softening astigmatism or spherical aberration. The lunar terminator was crisp and contrasty. Star clusters were sparkling collections of pinpoints. When panning across starfields, the field showed no barrel or pincushion distortion that can “warp” the field.

Stars did begin to distort with coma and astigmatism about 70 percent out from the center of the field, and were quite aberrated at the edge. Having stars sharper to the edge across a wider field is where higher-priced binoculars have the advantage. 

However, at their typical retail price of $140 U.S., Celestron’s Ultima 10x50s represent a terrific value in an affordable but high-quality binocular for astronomy. 

MSRP:  $140

Website:  www.celestron.com

About Alan Dyer

Alan Dyer is an astrophotographer and astronomy author based in Alberta, Canada. His website at www.amazingsky.com has galleries of his images, plus links to his product review blog posts, video tutorials, and ebooks on astrophotography.

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