How can I estimate the time that a photo was taken? [more inside]
posted by zvs on Aug 5, 2009 - 11 answers

Was the entire universe created by the Big Bang, or is the space/time generated by the Big Bang part of a larger universe? [more inside]
posted by Lownotes on Jun 23, 2009 - 23 answers

I am going crazy trying to get a sighting of Comet Lulin, and I don't want to blow the best chance tonight! I live east of Rockville, MD, and there is a fair amount of light pollution in the area. I just got a 6" Dobsonian Telescope (Orion XT6), but know very little about finding my way around the sky. [more inside]
posted by RobotNinja on Feb 23, 2009 - 7 answers

What planisphere would you recommend for 15 degrees South latitude? [more inside]
posted by jet_silver on Oct 9, 2008 - 3 answers

I would like help understanding the CHANDRA xray satellite mission. [more inside]
posted by reflecked on May 4, 2006 - 7 answers