Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy
moore positional » aware positional, pure positional, whole positional
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
more practical » some practical
patrick more » patrick moyes, patrick mkie, patrick mark

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 moore positional astronomy sergey ) OR ( the patrick more practical astronomy sergey )).
• Adding a wildcard symbol may retrieve word variants: (( the patrick moore positional astronomy sergey ) or ( the patrick more practical astronomy sergey ))*.