Tycho was a science fiction fanzine by John L. Gergen.
John Gergen was a science fiction fan from the late 1930s and the 1949s who was a member of the Minneapolis Fantasy Society.
Two issues of Tycho appeared, the first in June 1942. The cover was by Morris Dollens with a frontpiece by Sherman Schultz. Contributors of writing were George Dickson, Art Osterlund, A. L. Schwartz, and Sherman Schultz.
The second issue appeaed in Movember 1942, with a cover by Morris Dollens, and frontpiece by Sherman Schultz, and writing by Redd Boggs (Sky Hook), Donn Brazier.
As well, eh collaborated with Poul Anderson on the science fiction short story The Entity, which appeared in the June 1949 issue of Astounding Science Fiction. It was the fifth story ever published by Anderson, and the only story of Gergen's to be published in a prozine.