Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moore positional » aware positional, pure positional, whole positional
astronomy during » astronomy dialling, astronomy meeting, economy during
moore practical » more practical, moocs practical, mouse practical

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