Perhaps you should try some spelling variations:
practical astronomy » optical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moocs practical » mics practical, does practical, drops practical
moocs nautical » hoc nautical, logs nautical, nos nautical
patrick moocs » patrick moore, patrick mons, patrick moyes

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs nautical astronomy sergey ))".
• Adding a wildcard symbol may retrieve word variants: (( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs nautical astronomy sergey ))*.