The Konus 20 x 80mm KonusVue is a surprisingly able performer for such a reasonably-priced large aperture binocular. For about the price of many smaller and dimmer 8 x 42mm and 10 x 50mm binoculars, you get the immense light-gathering of two 80mm lenses (equal to two 3.1” rich field refractor telescopes, one for each eye). The KonusVue uses high light transmission BaK-4 prisms and fully-coated optics for bright images of faint deep space objects. Using two eyes to observe increases the resolution of small details by as much as 40% over the resolution visible when using only one eye when looking through a small rich field telescope.
While the KonusVue offers admirable astronomical viewing on its own, it also serves as a good wide-field observing complement to the narrower field of a telescope. You can get both a close-up view of a deep space object as well as a wide-angle view to put that object in context in the sky. With a reasonable 2.7° field of view, it excels at sweeping the star clouds of Sagittarius, searching out the Great Galaxy in Andromeda, taking in open clusters like the Beehive and the Wild Duck, and more. There is significant barrel distortion (straight lines away from the center of the field appear curved), but you very rarely observe straight lines in space and the effect is rarely noticeable. There is also some visible astigmatism and chromatic aberration at the edges of the field. However, these flaws are minor considering the binocular’s aperture and most observers (other than the most critical and nitpicky) will find them unobjectionable, particularly in view of the low price of the KonusVue.
The usable eye relief is quite good, at 14mm, although the image will vignette slightly for most eyeglass wearers. Soft rolldown eyecups shield the unaided eye from stray light when rolled up, and cushion eyeglass lenses when rolled down. The KonusVue has center focusing, like a conventional binocular, with a diopter adjustment ring on one eyepiece to match the binocular focus to your individual eyesight. With a close focus of 150 feet, it is not a general-purpose terrestrial binocular. That said, the KonusVue is a good choice for long distance terrestrial viewing under low light conditions. Nesting eagles or ducks across a lake at dusk are prime candidates for this big binocular. As a first serious astronomical observing tool, as a long distance nature study instrument, or as a highly useful companion to take into the field with your telescope at night, the Konus 20 x 80mm KonusVue is a very worthwhile balance of good performance versus low price.
The KonusVue binoculars use a molded polycarbonate body to keep the weight down below other 20 x 80mm binoculars, although the still weigh in at a stout 4.65 lbs (74.5 oz.) Using the binocular on a tripod is virtually mandatory, as few people will have the wrist strength needed to hold them steady enough for extended hand held use. For tripod use, a reinforcing bar runs from the prism housings to the objective lenses. In addition to providing structural rigidity that keeps the optics firmly collimated, it provides a sturdy support for the integrated photo tripod adapter. The tripod adapter can slide along the bar to balance the binocular on a tripod, no matter what part of the sky you are viewing. Once you find the correct balance, a large thumbscrew locks the adapter in place.
The binocular is fully clad in protective rubber armor. While the armor provides a more comfortable grip in cold weather, and protects the collimation of the optics against bumps and knocks, it does not make the binocular waterproof or fogproof.
The binocular comes with protective covers for the eyepieces and the objective lenses. The supplied woven neck strap is acceptable for occasional use. However, adding a wide heavily padded neck strap would be a comfortable addition if the binocular must be carried extended distances to an observing site. A lightweight hard carry case with carry strap completes the package.