Grand Historical Big Binoculars Show

Grand Big Binoculars World

The history of Nippon Kogaku began from binoculars.
In Nikon Kenkyukai Tokyo, many binoculars have been taken up to the theme of research.
The Nikon Kenkyukai reported the research on old big binoculars two years ago.
Historical / Optical Study of Big Binocular Telescope in the Showa Era
Many Nippon Kogaku enthusiast said that this report was very interesting.

The Nikon Kenkyukai Tokyo Meeting in June was held in Harumi near Tokyo bay, and we researched the historical old vintage NIKKO big binoculars again.

The Program of a Study Meeting

Presentation Session

Shigeki Terada, an engineering specialist of the Dodaira astronomical observatory, a member of the Nikon Kenkyukai Tokyo, a director of the telescope division talked about his great work.
Let's enjoy a presentation program in Tokyo Meeting together.

Shigeki Terada's Excellent Presentation

You can download his pdf document.
Please understand his lecture, looking at this pdf document.
Now, please start Terada-san lecture.

Special Download
A Historical and Optical Study of Big Binocular Telescope in the Showa Era - Part 2 -
Japanese (PDF)
This Japanese PDF file was made for Nippon Kogaku enthusiast.

In the last paper, I reported about pre-WWII High view angle binocular telescope and Showa 30' era (around 1955) binocular telescope.
Recently, I have got some new samples and then had chances to restore and investigate those samples.
I would like to describe some topics that found out during those restorations.

Sample No. 1 :
10 cm 70 deg. declination 15x High view angle binocular telescope made by Enomoto Optical Instrument Works (with Nikko fork mounting)

This is owned by Choukou soy sauce and soy paste manufacturing association, Ohmura-cho, Nagasaki Prefecture.
I got a chance to restore it from February 2010.
Specified Model of Nikko local code is "JOG high view angle binoculars" and IJA code is "model 89 10 cm Anti aircraft binoculars".
Serial No. is 2011, And there are some engravings on the body. Assumed manufactured period is Showa-17 (1942) , made at their Ohmiya plant, Saitama prefecture.
Because Enomoto was absorbed by Fuji photographic film in 1943, using glasses are assumed made by Fuji optical glass. But glass n-Abbe number measurement of rhomboid prism by spectrometer is indicated BK7, and glass maker seems to Nikko glass according to REPORTS OF THE U. S. NAVAL TECHNICAL MISSION TO JAPAN (Ref. : USNTMJ Report X-05).
Optically, this is very similar to Nikko's same model that last time mentioned, but rhomboid prism is not silvered. Objective and eyepiece design are also very similar to Nikko's, but curvature is slightly different.
This difference is indicated curvature standard is not Nikko's but is Enomoto's. Hence, this optics is made by Enomoto's optical works. Viewing Impression is very good, and any differences from Nikko's same model are not found.
This result shows Enomoto's high engineering level. (Enomoto is former Fujinon!)
Also mechanically, compatibility to Nikko's is almost perfect. Original painting color is hidden inside of the lens shade of objective. It is IJA's yellowish gray. But repainted to IJA's dark green.
Fork mount is made by Nikko. Serial No. is 3925.
Fork is made with aluminium alloy except bronze screw, and horizontal indicator is made with bronze.

Sample No. 2 :
10 cm 70 deg. declination 15x High view angle binocular telescope made by Nikko

This is the one reported last time. Model is same as sample No. 1.
Serial No. 274. Year of manufacture is Showa-12 (1937) .
Another same model which a guest showed us at the day is serial No. 4069.
It seems that year of manufacture is Showa-14 (1939).

Sample No. 3 :
12 cm 45 deg. declination 20x High view angle binocular telescope made by Nippon kogaku

Serial No. 8015. Because trade mark is pointed it is made after WWII. It seems that year of manufacture is Showa-33 (1958) .
Specified model is "JF high view angle binoculars II" (standardized model). All transparent surfaces of optics is mono layer coated. Desiccation control is done by silica gel and moisture indicator (CoCl2 paper) .
Mechanically, mating part to mounting is completely same as 12 cm 20x binocular telescope reported last time.

Sample No. 4 :
12 cm 20 deg. declination 20x High view angle binocular telescope made by Toyokawa naval works (with Nikko fork mounting & tripod)

Serial No. 504, it was manufactured in February Showa-20 (1945) .
It was six months before deadly air raid at 7th August 1945.
Specified model is "JF high view angle binoculars IV". This is not "Standardized model".
One optical feature is its gigantic modified porro II prism. This optics consisted by porro II prism and rhomboid prism, so that optical pass became very long.
It let upper prism of porro II be so big. And to make 20 deg. inclination, opposite side upper prism has unusual shape. Those glass is very similar to Fuji's BK7. All optics is not coated. Viewing impression is very good, and similar to other 12 cm models. 20 deg. depression position is prominently comfortable.
One mechanical feature is its many evidences of material shortage occurred in the last period of WWII. But it is not "standardized model". Weight is 23 kg.
Main body is made with poor quality alminium alloy, and machined roughly. To make it air tight, many mating part is covered with waterproof clay and rubber seal. Bronze parts are found only around moving pats and screws facing outside. Furthermore, some inside parts are made with iron!
Eye distance adjusting mechanism has the traces of original "8" shaped steel belt around between 2 prism barrels, but there is no belt and its right side (has a reticle) prism barrel is fixed, only left side can be moved.
This sample has rare wood container, and it contains bulbs for lighting its reticle. This bulb is made by Fuji electric, spec. is 20V2W-1cp (candlepower).
Attached fork mounting and tripod are made by Nikko, serial No. 169, manufactured period is Showa-14 (1939). It is very heavy (34 kg) , and all parts are made with bronze or brass, because anti-corrosion by seawater and before spread of using stainless steel. Opening distance of fork is 300 mm, it is for pre "standardized model", and cannot mount "standardized model".
Desiccation control is done by same method as sample No. 3. However, cap is round screw cap.

12 cm 20 deg. 20x, Made by Toyokawa Naval Works

Sample No. 5 :
12cm 20x binocular telescope made by Kowa optical instruments works

This sample came from Sasebo, Nagasaki prefecture. There is no inscriptions.
By distinctive shape of eye distance adjustment belt cover, this model specified to Model 65 type 12cm binocular of Japan Maritime Self-Defence Force (Post WWII model of "JF binoculars type I"). Still now Kowa is using "8" shape steel belt to adjust eye distance and the cover of this belt dividable to 2 parts.
This is not "Standardized Model". All transparent part of optics is applied mono layer anti-reflection coating. Hence, this is a post-WWII product. May be 1960's.
Desiccation control is done by same manner as sample No. 3.
Desiccant cap has round shape, but secured by 6 screws.

Sample No. 6 :
12cm 20x binocular telescope made by Nippon Kogaku

This is the one reported last time. It has many character of "Standardized Model".
Assumed manufacture period is 1957 because serial No.7230. Specified model is post-WWII model of "JF Binoculars Type I".
There is a name plate "12cm binocular telescope type I" and triangular Nippon Kogaku Tokyo mark. This is the commercial model for fishing industry etc..
Desiccation control is done by same method as sample No.3.

Sample No. 7 :
12cm 15x binocular telescope for nocturnal mission (for torpedo attack) made by Nikko

This sample is owned by a member of Nikon Kenkyukai.
Serial No.114. There is a inscription of Japanese letter "Mizu" (water) on the left prism case.
Then this is for torpedo attack. Specified model is "JF Binoculars type III".
There is a sign "7. 12. 17"on the porro II prism by pencil, this means the date 17th December Showa-7 (1932). Probably, it should be manufactured in 1933.
One optical feature is its 15x low magnification. By means of the 8 mm exit pupil diameter, Observer can avoid the misalignment of his eye pupil and exit pupil of eyepiece caused by the ship rolls and pitches.
To achieve this magnification, its porro II prism becomes to extra big size. The glass index is very similar to Nikko's BK7. All optics is not coated.
Viewing impression is excellent, because this low mag. helps to decrease relative chromatic aberration. Furthermore, flatness and distortion of field of view is also very good.
Mechanical features are its very heavy weight and gorgeous usage of every materials. Lens shade and outer cell of objectives, big prism cases, every moving parts are made of bronze.
The body tube is made of very thick aluminum alloy. Weight is 23.5 kg.
Eye distance adjusting mechanism is original "8" shaped steel belt around between 2 prism barrels and the adjusting screw scale.
There is no desiccation control done by silica gel and moisture indicator (CoCl2 paper) except inner air exchanging holes. Desiccation control mechanism by silica gel and moisture indicator assumes to be applied from middle of 1930's.
The design of mating part to mounting is differ from the high view angle binocular telescope. There is no elevation angle gauge and its indicator.
Usually, high angle bino cannot balance to turn its objective horizontally, but this model balances to turn horizontally.

Impression and Fact

In addition, I would like to say my impression and fact through the research.

1. Nikko local codes

There are some occasions that different Nikko local codes applied to one optical design.
Those are assumed as one is for "Pre-Standardized model", another is for "Standardized model".

2. Compare with new Nikon

Thanks of that day's guests, There is an opportunity to compare these old models with brand-new Nikon 20x12cm binocular telescope type III (Multi-coated).
It is a matter of course Type III's extra high contrast obtained by its clean, multi-coated optics, but flatness and distortion of field of view have no difference.
Because "Type III" is also "Usual" achromatic, The chromatic aberration is also similar to the old models. And, type III's fork mount is completely compatible to "Standardized model"' such sample No. 3 and No. 6!
This fact is very valuable. We can use the brand-new mounting for our old collections!!

3. Great German and Japanese old binoculars

Also, the guest brought "eug" (The Optical Precision Works in Warsaw) 10x80 antiaircraft binoculars (with mono-layer antireflection coating) .
By comparison, viewing impression of eug is little better or similar to those Japanese models. It means optical part engineering level of the binoculars at that period in Japan is nearly attained to the world level.
But machining engineering level seems obviously inferior to Zeiss.

4. Change of design

And another guest brought "Pre-standardized model" 12cm 45deg. declination 20x High view angle binocular telescope.
By comparison with the above No. 3 (Standardized model) , many KAIZEN of productivity points are found especially around prism cases.

5. Delay of radar development

However, this outstanding significance of the binoculars technology development might mean the clear evidence of prevention of the radar technology progress in Japan.
This time, fortunately, some precious samples from 1933 pre-WWII to 1945 final period of WWII, furthermore, post-WWII era could be investigated and compared.
In this comparison, some technical transitions mentioned on literature were observed on original. And some new findings are acquired.
Especially, those samples showed the attitude to keep the primary objective - Optical Spec. - not only with gorgeous usage of materials and skills before WWII but also with the destitution of them in final era of WWII.

During these restorations, I found some signs or imprints written by factory workers or soldiers of those days.
They were alive at those days, and they really made, used and repaired these binoculars.
This report should be a letter of thanks for their hardships and spirits.

Shigeki Terada
An engineering specialist of the Dodaira Astronomical Observatory
A member of the Nikon Kenkyukai Tokyo, Director of the Telescope Division

Show and Tell

Let's join the Tokyo Meeting with us.
You can touch the super collection by your internet PC.
Very beautiful vintage optical weapons, big binoculars, high view angle binocular telescopes and little Mikron with you.
They are old, but great collection.

Tokyo Meeting in Summer

Very Beautiful Vintage Optical Weapons

Vintage Binoculars are Stored by the Strong Wooden Box

12cm 20x Binocular Telescope by Nippon Kogaku 1939

12 cm 20 deg. 20x, Made by Toyokawa Naval Works 1942

Yukikazu Hayashi is Explaining the German Binoculars

The German eug 10x80 antiaircraft binoculars shown in the following photograph is very good collection with the outstanding optical performance.
This binoculars was restored by Mr. Antony L. Kay of British OptRep.

Very Good Condition eug 10x80 Antiaircraft Binoculars
Restored by Mr. Tony Kay of world famous Britain

A Small Precise Optical Weapon

Very Rare Small Vintage Binoculars

Who Placed the Stereo Nikkor Here?

Akihiko Suzuki is Explaining the Special Mikron

Special Mikron Binoculars

Terrace Session

We went out, and verified the super performance of big binoculars actually.
Do you have the experience of watching the far world with old vintage NIKKO big binoculars?
We looked at Harumi pier in Tokyo with old vintage big binoculars.

The Vintage Big Binoculars Carried into the Terrace

From the Very Old Model to the Newest Nikon Binoculars

The Historical Big Binoculars Installed on the Terrace

Terada is Doing the Final Adjustment of Binoculars

The Binoculars which Turn to the Zenith

The Kenkyukai Members Enjoyed the Wonderful View

The Nikko Binoculars with the Highest Optical Performance
Restored by Mr. Tony Kay of world famous Britain

The Big Binoculars Turned to the Tokyo Harumi Pier

Our old vintage binoculars found two warships which are anchored at the Tokyo Harumi pier. According to the press news, they were JS Ise (DDH 182) and USS Blue Ridge (LCC 19).

A reception and social events are due to be held on these ships from tomorrow.
We watched the sailors of full armaments on the ship by old vintage binoculars.
However, if it sees in detail, the sailors will also watch us with Navy binoculars onboard!!

USS Blue Ridge ( LCC 19 ) to Visit Harumi

Probably they will have said like this.
"Many guys are watching at us with very very old junk binoculars!!"

12 cm 20 deg. 20x, Made by Toyokawa Naval Works

It is engraved as Showa 14 (1939) June

Big Happy Binoculars Meeting

It was a fantastic and happy meeting.
18 sets of old vintage binoculars and binocular telescopes gathered today.
We understood that old vintage binoculars have the great performance if you maintain them with love.
At the dinner party, we enjoyed delicious beer.

Nikon Kenkyukai Tokyo Meeting

Today's Leading Roles are These Wonderful Vintage Binoculars

Related Links

OptRep, Optrep Optical Repairs
Mr. Antony L. Kay of world famous Britain, Technical director of OptRep
May 2011 Meeting of Nikon Kenkyukai
Grand Vintage NIKKO Super Deep Saturday
October 2010 Meeting of Nikon Kenkyukai
Historical/Optical Study of Big Binocular Telescope in the Showa Era