Perhaps you should try some spelling variations:
optical astronomy » spherical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
astronomy series » gastronomy services, astronomy survives, astronomy studies
moore optical » moire optical, more optical, moon optical
core nautical » some nautical, core analytical, board nautical
patrick core » patrick corr, patrick corsi, patrick coyle
core optical » large 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 core optical astronomy series ) OR ( the patrick core nautical astronomy series )))).
• Adding a wildcard symbol may retrieve word variants: (( the patrick moore optical astronomy sergey ) or ((( the patrick core optical astronomy series ) or ( the patrick core nautical astronomy series ))))*.