Sorry, I dissed on the scope a bit.
he manufacturer of the Weatherby "Imperial" and "Imperial Variable" scopes was Hertel & Reuss.
What I could find out about it is that Hertel & Reuss was a German company based in Kassel, which produced different optical instruments (microscopes, telescopic sights, binoculars). Hertel & Reuss existed from 1927 to 1995, when it finally became insolvent and was incorporated into another company. It's still known under the same name and they make opera glasses:
http://www.hertelreuss.com Looks like they still make good stuff.
From what I found in the Weatherby book, Roy Weatherby went to 4 different optics companies in 1953: "Of these four, [Roy] was most impressed with Hertel & Reuss, which had an excellent reputation as one of the finest optical companies in Germany."
