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

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 ((moore nautical) OR (board 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 ((moore nautical) OR (board nautical)) astronomy sergey ))".
• Adding a wildcard symbol may retrieve word variants: (( the patrick moocs practical astronomy sergey ) or ( the patrick ((moore nautical) OR (board nautical)) astronomy sergey ))*.