One of the charts located in the above link (use Chrome and it asks to automatically translate) is a year by year manufacturing location, whether or not the company was incorporated, and the type of logo on the label. I am providing a translated version of that with the top rows showing the city (Tokyo), the section of the city, and then the street address separated by dashes. The timeline across the top of the two sections is in both Gregorian years and Showa years (year of reign of the Emperor). Beneath that are two rows showing when Goto Optical was a private company and when it was incorporated. I have added whether or not the labels show patent information or not. Finally the lower rows show a particular logo type.
Things changed pretty rapidly in the first few years on that score, and then settled into Zeus for the pre-WWII years. You can also see that Goto was a corporation from 1938 to 1941 (my Apollon label shows these incorporation characters and allows me to date it within that range). Kodama-san did not display in his label picture the Zeus label that accompanied my first Uranus telescope and an Eros telescope, both with patent information.
Since this label does have patent information I believe that it is dated from when Goto started selling telescopes again after WWII (1947). Again patent inclusion on the label is for those years in orange. So I have indicated both a Zeus logo for those years and patents in the label. Other information on the Eros (instructions date inside lid) allow me to focus further to 1951-52 for that scope. I can't do any better than '47-52 for the Uranus.
So I have a pretty clear date for that Eros within two years and the Uranus within six years. Also I previously thought it a Type 3.5 Uranus (a mix). The lens cell, the focuser and the lens cap are Type 3. The attachment of the altitude rod to the OTA is Type 4. The case build is also Type 4. Kodama-san looked for changes that would allow him to apply Type 1-5 designations for a Uranus scope. His complete discussion of Uranus Types is at this site (again Chrome allows direct translations)
I think things were a little more fluid, with changes made as they needed to be, and the only capture of current build is in the advertising. So Type number of Uranus in general is a little fuzzier. Finally, since we know that the label on my Apollon case was the last label used before the war; and the patent adds were after the war; and that the Uranus Type 4 designated by Kodama-san was built from '47 to '54, that my first Zeus Uranus (Type 3.5 mix) was sold as a Type 4, but likely early.
The Uranus I just received is clearly by all designations a Type 4, except for the case build. It doesn't have a case label but I think it is a late Uranus Type 4. My brother is a photographer and has been printing on aluminum sheet for a couple years. I had him make me some replica labels and this is the label that I will add to the newest Goto Uranus to replace the missing one (Sorry for poor picture quality. It's much sharper than my little pocket cam has captured).
Finally I previously thought that the 'GOTo' logo was limited to only '53-'54, so I had this Uranus and Eros nailed down to two years as well. The Uranus went to a Type 5 in '55 so there two years is good. But I hadn't really looked at the labels on my '55-'61 telescopes. They are also 'GOTo' logo'd. So that would mean that all these telescopes, and indeed all the school telescopes sold in Japan during the late 50's were likely labelled the same. Goto-san bought a factory in 1942 during the war. The location was Setagaya - Shinmachi 1-115. It was in use from '43-'63. So I have to believe that the 'GOTo' logo, which states Setagaya as the location, was used on telescopes made there the much longer eleven year period. In 1963 the factory moved to the Fuchu-chi section of town and the 'GOTO' logo label clearly indicates that.
So I have made a few modifications to Kodama-san's chart. I think given the data they are logical. I have forwarded these changes to him and am waiting for a response.
Since the Goto telescopes we see here on CN are predominately from the Setagaya factory, how can we nail down things further. Certainly the inspections tags that accompany the scopes will help, as well as the fliers that Goto published. I have yet to get a clearer indication of the date of my second Eros with the 'GOTo' logo. But now I will go to advertising fliers and catalogs and try to sort it out. More to come.
Edited by Stew44, 02 March 2019 - 09:07 PM.