Perhaps you should try some spelling variations:
practical astronomy » optical astronomy, positional astronomy
mpondo practical » upon practical, bonds practical, bono practical
astronomy sergey » astronomy survey, astronomy surveys, astronomy seven
patrick mpondo » patricia opondo, patrick bond, patrick mons
n nautical » _ nautical, a nautical, 2 nautical
patrick n » patrick _, patrick a, patrick d

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