Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, positional astronomy
optical astronomy » nautical astronomy, spherical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
moore optical » moire optical, core optical, moon optical
patrick more » patrick moyes, patrick mkie, patrick mark
more optical » moire optical, core optical, more optimal

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