Bad Astronomy (http://blogs.discovermagazine.com/badastronomy/).
Blog run by Phil Plait. Phil Plait is a skeptic, astronomer and author of the book "Bad Astronomy". The Bad Astronomy Blog is moving to Slate magazine on November 12.NASA (http://blogs.nasa.gov/).
Actually a series of blogs, each one run by a different NASA scientist or engineer.The Planetary Society (http://planetary.org/blogs/).
Also a series of blogs, covering a variety of topics in planetary science, exploration and advocacy.Star Stryder (http://www.starstryder.com/).
Blog run by Pamela Gay. Pamela Gay is assistant research professor in the STEM center at Southern Illinois University Edwardsville. She cohosts the podcast Astronomy Cast (along with Fraser Cain) (See http://www.astronomycast.com/).