Perhaps you should try some spelling variations:
practical astronomy » optical astronomy, positional astronomy
astronomy sergey » astronomy surveys, astronomy seven, astronomy large
astronomy survey » astronomy surveys, autonomy survey, astronomy surveying
moocs practical » books practical, mics practical, colts practical
moore nautical » board nautical, mile nautical, moore national
patrick moocs » patrick mons, patrick moyes, patrick moore's

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs practical astronomy survey ))) OR ( the patrick moore nautical astronomy sergey )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs practical astronomy survey ))) or ( the patrick moore nautical astronomy sergey ))".
• Adding a wildcard symbol may retrieve word variants: (((( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs practical astronomy survey ))) or ( the patrick moore nautical astronomy sergey ))*.