Allan Sandage, one of the greatest astronomers of the twentieth century, has died at the age of 84. Sandage, who worked with Edwin Hubble as an assistant at Mount Wilson Observatory, played an integral part in increasing our understanding of the scale of the Universe and determining the Hubble Constant, which describes the Universe's expansion.
Click on the Astronomy Now link below for further details. (http://www.astronomynow.com/news/n1011/16Sandage/)