Astrobites: Read about some of the lates and most exciting papers and discoveries in the field of astrophysics - One paper is described per day, and the authors are astronomy graduate students. Check it out!
APOD - Astronomy Picture of the Day... The name says it all.
Astro Anecdotes (by Anders Overaa Thygesen) gives some of the untold stories and anecdotes from the world of astronomy. Very entertaning!
NASA - The National Aeronautics and Space Administration. Here you can read the latest news from NASA.
Data and literature search
Just for Fun
Kepler and K2 science center. Here you can learn about the Kepler and K2 missions, coming K2 observations, useful data analysis tools etc.
Groups, collaborations, and instruments
Learning and analysis tools
Bad Astronomy, the great astronomy blog by Phil Pliat.
Astrophysics data system, aka. "Bumblebee" is a beta version of a new version of the ADS, which allows you, among other things, to make full text searches. Worth a visit!
ArXiv is an open e-print service where many publications can be found before their official publication in a scientific journal.
ArXiver is a site which brings you the daily updates from arXiv, but with the addition of a figure from the individual papers.
MAST - The Mikulski Archive for Space Telescopes is a NASA funded project to support and provide to the astronomical community a variety of astronomical data archives.
Lachend Wakker Worden ("Wake up laughing") is the personal english/dutch blog by my good friend and colleague Vincent van Eylen.