Perhaps you should try some spelling variations:
practical astronomy » positional astronomy
optical astronomy » spherical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy large
moocs practical » mics practical, clocks practical, colts practical
astronomy seven » astronomy some, astronomy science, astronomy between
patrick moocs » patrick moore, patrick moyes, patrick moore's
mons nautical » logs nautical, nos nautical, hoc nautical
patrick moon » patrick moore, patrick mein, patrick moloney
moon optical » ion optical, non optical, photon optical
patrick mons » patrick moyes, patrick bond, patrick mpondo

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 moon optical astronomy sergey ) OR ( the patrick moocs practical astronomy seven ))) OR ( the patrick mons nautical astronomy sergey )).
• Adding a wildcard symbol may retrieve word variants: (((( the patrick moon optical astronomy sergey ) or ( the patrick moocs practical astronomy seven ))) or ( the patrick mons nautical astronomy sergey ))*.