Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy
moocs positional » holds positional, blocks positionals, images positional
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moore practical » more practical, moocs practical, mouse practical
moocs nautical » moocs practical, logs nautical, nos nautical
patrick moocs » patrick mons, patrick moyes, patrick moore's
hoc nautical » nos nautical, hoc analytical, logs nautical

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