Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy, positional astronomy
astronomy series » astronomy sergey, gastronomy services, astronomy survives
moocs practical » mics practical, does practical, drops practical
patrick moocs » patrick moore, patrick mons, patrick moyes

You may be able to get more results by adjusting your search query.

• Adding a wildcard symbol may retrieve word variants: the patrick moocs practical astronomy series*.