Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
patrick mpondo » patricia opondo, patrick bond, patrick mons
patrick moyes » patrick keyes, patrick mayen, patrick mons

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