. This is the first time I've come across this monocular set.
It comprises an 8×24 and a 6×18 monocular with interchangeable objectives.
The 8×24 is marked 8 power wide-angle 8.2°.
The 6 x 18 is marked 6 power wide-angle 11°.
The instrument is extremely well made, metal with a finish to a very high standard.
It has an almost unmarked Japanese Passed oval yellow sticker, with lettering in red and green, and the monocular is marked Japan in white letters.
I will have to check further whether the emblem means Miyauchi.
The images are good, both star images and in the daylight.
There is some pincushion distortion and some variable field curvature.
This would be a great instrument even today except for a major failing.
It is almost totally uncoated on all surfaces except one surface of each of the objective choices has a good quality single coating.
I expect the transmission to the slightly under 60%.
There is a small amount of squaring off of the exit pupil also.
In use, at night in the presence of say a street light or perhaps the moon, there are very serious multiple large ghost images.
These are also noticed during the daytime, but to a lesser extent. Some seem to come from prism surfaces.
This would be a great instrument even today if it was fully multicoated on every surface.
The monocular set dates I think from the 1960s.
The pouch, which is well made, contains an inner pouch where the 6 times objective fits and can be buttoned-down. The 8 times objective also fits in the pouch but cannot be buttoned down. The monocular also fits in the outer pouch with either objective fitted.
I will use it with the 6 times objective as it is then tiny and the measured field is 11.15°. The instrument almost completely disappears in the palm of your hand.
With the eight times objective it also almost disappears and the measured field is 8.05°.
So I think that one or both of the magnifications are very slightly different from what is marked.
I have a very small 6 times monocular, but the field is 7.5°. The Bicky monocular at 6 times, however, covers 11.15°, which is more than double the area.
This is an interesting device, but it is a great pity it is not coated on every surface. It could have had such single coating even if multi coating was probably not around commonly in Japan at that time.
It comprises an 8×24 and a 6×18 monocular with interchangeable objectives.
The 8×24 is marked 8 power wide-angle 8.2°.
The 6 x 18 is marked 6 power wide-angle 11°.
The instrument is extremely well made, metal with a finish to a very high standard.
It has an almost unmarked Japanese Passed oval yellow sticker, with lettering in red and green, and the monocular is marked Japan in white letters.
I will have to check further whether the emblem means Miyauchi.
The images are good, both star images and in the daylight.
There is some pincushion distortion and some variable field curvature.
This would be a great instrument even today except for a major failing.
It is almost totally uncoated on all surfaces except one surface of each of the objective choices has a good quality single coating.
I expect the transmission to the slightly under 60%.
There is a small amount of squaring off of the exit pupil also.
In use, at night in the presence of say a street light or perhaps the moon, there are very serious multiple large ghost images.
These are also noticed during the daytime, but to a lesser extent. Some seem to come from prism surfaces.
This would be a great instrument even today if it was fully multicoated on every surface.
The monocular set dates I think from the 1960s.
The pouch, which is well made, contains an inner pouch where the 6 times objective fits and can be buttoned-down. The 8 times objective also fits in the pouch but cannot be buttoned down. The monocular also fits in the outer pouch with either objective fitted.
I will use it with the 6 times objective as it is then tiny and the measured field is 11.15°. The instrument almost completely disappears in the palm of your hand.
With the eight times objective it also almost disappears and the measured field is 8.05°.
So I think that one or both of the magnifications are very slightly different from what is marked.
I have a very small 6 times monocular, but the field is 7.5°. The Bicky monocular at 6 times, however, covers 11.15°, which is more than double the area.
This is an interesting device, but it is a great pity it is not coated on every surface. It could have had such single coating even if multi coating was probably not around commonly in Japan at that time.
