It is the taking lens for the Minolta All-Sky-System.
All images and information are from a Josef Scheibel article, from Photo-Technik un Wirtschaft n.6 1973
28.8mm filters, Leica m39 screw mount, 200 degrees circular fisheye, 28.8mm flange focal distance. 35mm film cameras.
links
- Link to the article on Scheibel pages, http://fachliteratur.scheibel.de/FE_PTW_1973.pdf
- http://www.scheibel.de/