This is a lens from a Soviet Spy satellite Yantar 4K2(Amber-4K2) from a camera system Zhemchug-18 (Pearl-18).
1330mm lens length, 470mm lens diameter.
http://www.ss.ua/msg/ru/electronics/photo-optics/objectives/albmg.html

http://www.ussrphoto.com/UserContent/1272016_electronics-photo-optics-objectives-3.800.jpg

http://www.ussrphoto.com/UserContent/1272016_electronics-photo-optics-objectives-1.800.jpg
But of course nothing beats in size the Mezon-2A lens from a older satellite Yantar-2k - KMZ Mezon 2A - 500KG monster

http://www.ussrphoto.com/UserContent/1272016_mezon-2a.jpg
Vlad