Here are some free courses you might like to try out from the Open University:
http://www.open.edu/openlearn/science-maths-technology/free-courses
Click on Astronomy in the left hand filter bar.
There are courses on:
- The Sun
- Moons of our Solar System
- In the night sky: Orion
- Galaxies, stars and planets
- The Moon
- Active Galaxies
- Jupiter and its moons
- And many more… all free…