Yes, made in the Early 1950's by a famous West German company who made only telephoto lenses... 250mm to 500mm.. The lens had 2 mounts, Exacta, (Original) and M42 (What I have) for Pratica - A W-German SLR. The M42 apparently was made in lowers numbers because that the Exacta was more popular back then in Europe.

It two focusing versions -- Rack/Pinion (What I have), and the more common Helical focusing in modern lenses.

It had 2 or 3 optical versions... Original 2 element (What I have) and a 3 and or 4 element (the latter 1 or 2 elements set closer to the mount.

In the 1960 or 70's  the "Tele Astranar" line was bought by Japan, and made it much cheaper and sold many different "Branding s" for under $200.00 (Soligar, Vivitar, Star, etc). My lens is built with steal or some heavy medal. It has 16 Iris blades, and has a blue single coating., and I can use to bop a thief on the head if needed, and not damage the lens 

I traded a Nikon N50 with 2 kit lenses. and spent $50.00 to have the blades put back in, and cleaned up. I have heard that this version has sold for over $300.00 in 100% working order.. But, they rarely show up on eBay... I had no idea of the quality I was trading for, I got lucky. 

Somewhere in my past posts, Is a little more info.

Steel huh? is it heavy?