Large spiral galaxy in Ursa Major, 1960
Photograph of a large spiral galaxy in Ursa Major. "A large spiral galaxy in Ursa Major, photographed in 30 minutes in blue-violet light with the 120-inch telescope. This giant stellar system at a distance of about 8 million light years is barely resolvable, in the spiral-arm structure, into groups of individual brightest stars, dark dust lanes and luminous gaseous clouds. But most of the light comes from myriads of unresolved fainter stars that are highly concentrated toward the bright central region. The beautifully curved spiral arms suggest rotation, which is confirmed by spectrographic [sic] observations. They indicate that innermost parts revolve in a period of 30 million years, while the outermost regions lag behind in a period of the order of 100 million years" -- typed note attached to verso. "Please return to: Public Information, University of California, Berkley 4, Calif." -- stamped on verso. Verso dated, "March 3, 1960".
EXMASTGALEXTSYS0041EXMPSASTGALEXTSYS004EXMPSASTGALEXTSYS0041Astronomy Galaxies and Extragalactic Systems