Miyauchi 20×77 Angled Binoculars (Exceed BS-71i) Review

MECHANICS AND FOCUSING SYSTEM

The Miyauchi 20x77 astronomical binoculars feature a very attractive design, with soft, modern lines. This optical instrument can also be appreciated as a decorative piece on cloudy nights. It is incredibly compact, almost comparable in size to classic 50-63 mm porro prism binoculars.

Fig.1 – The Miyauchi 20×77 binoculars, in the foreground, Vixen Ultima 9×63 on the left and Fujinon FMTX 10×50 on the right

 

Focusing is individual and occurs by rotating the area near the eyepieces. Movements are fluid and smooth, and this characteristic did not fail, even when observing at -10 degrees in high mountains.

OPTICS

Goals

These binoculars are composed of two semi-apochromatic doublets, each comprising four elements in three groups with a multilayer coating, including two ED elements. They are protected by two retractable lens hoods and have delivered excellent performance with saturated, bright colors. I noticed only a slight residual chromatic aberration when observing the brightest stars.

Eyepieces

The eyepieces (Reversed Kellner) are angled at 45 degrees with respect to the two 77mm ED objectives: this allows a comfortable view of deep-sky objects close to the zenith, without straining the observer's neck and shoulders. I believe this is the real "added value" compared to classic binoculars like the Fujinon 16x70. These accessories are removable, but you cannot use common astronomical eyepieces with a 31.8mm barrel, as you must purchase the eyepieces specifically designed by Miyauchi.

The exit pupil of 3.85 mm with the standard eyepieces is well usable even under medium-polluted skies, the eye relief, of 19 mm, is also good, The weight is 2500 grams.
The lens hoods are removable, the inside of the optical body is perfectly blackened, and the interpupillary distance adjustment system is comfortable and precise. The eyepiece attachment method is excellent.

 

IMPRESSIONS ON THE FIELD

 

We also appreciated the optical rendering of the Miyauchi 20×77 Exceed Binocular, an opinion also supported by a couple of friends who are expert deep-sky observers.

The ED doublet provides very bright and pinpoint images., although from hearsay, it seems that they do not reach the pinpoint quality of the 60mm diameter model. The eyepiece arrangement is comfortable, similar to that of the large 125mm diameter Vixen. During some evenings at high altitude, observing some galaxies and the Orion Nebula, I noticed how the performance of these binoculars was comparable to that of a telescope with a 120mm diameter objective.
I still fondly remember the almost photographic view of the Pleiades and the Andromeda galaxy M31, flanked by its satellite galaxies NGC 205.  

Rather difficult objects like the Crab Nebula M1, however, are easily visible even under moderately polluted skies. Furthermore, it is possible to resolve many star clusters, which are often contained together within the field provided by these binoculars; one example among many: the star clusters M46 and M47 near Canis Major.

 

PROS AND CONS

Merits

• Qconstructive quality
•  Prism angle perfect for astronomical observations
•  Possibility to change eyepieces
•  Excellent brightness of the lenses
•  Retaining value in the used market
•  Compact  

 

Defects

• Not as sharp as the Miyauchi Saturn II long focal length binoculars
•  Astronomical eyepieces cannot be used
•  More expensive than the classic 20x80 binoculars made in China

 

IN SUMMARY

I really appreciated the Miyauchi 20x77 binoculars. They are high-quality mechanical binoculars, with ED optics that reveal only a trace of residual color, and with the possibility of comfortable observation thanks to the angle of the prisms. They are not among the cheapest, but they are certainly a special product to use and own.

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