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

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 moore optical astronomy survey ))) 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 moore optical astronomy survey ))) 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 moore optical astronomy survey ))) or ( the patrick more optical astronomy sergey ))) or ( the patrick more practical astronomy sergey ))*.