Hi,
I have completed a number of courses through Coursera and they have all been great. I have completed courses on cosmology, astronomy, mechanics calculus etc and they have all been very user friendly and often entertaining. There is something about watching an enthusiastic calculus lecturer at 1.5x that makes me laugh...
The course "Astronomy: Exploring Time and Space" starts on 15 February.
https://www.coursera.org/course/astro
Duncan