Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy
astronomy series » gastronomy services, astronomy survives, astronomy studies
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moocs positional » holds positional, blocks positionals, images positional
moocs practical » books practical, colts practical, coins practical
mics practical » ics practical, micro practical, abcs practical
patrick moocs » patrick moore, patrick mons, patrick moyes
patrick mics » patrick mons, patrick michel, patrick maill

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