RT @cosmos4u: A brief obituary for John Dobson from “his” San Francisco Sidewalk Astronomers: sidewalkastronomers.us/2014.01.01_arc… – timeline filling up …
RT @cosmos4u: A brief obituary for John Dobson from “his” San Francisco Sidewalk Astronomers: sidewalkastronomers.us/2014.01.01_arc… – timeline filling up …