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 » books practical, mics practical, colts practical
astronomy seven » astronomy some, astronomy science, astronomy between
patrick moocs » patrick moore, patrick moyes, patrick moore's
moocs optical » moon optical, topics optical, cmos optical
mons nautical » logs nautical, nos nautical, hoc nautical
bond nautical » board nautical, hoc nautical, logs nautical
patrick mons » patrick moyes, patrick mpondo, patrick timony
patrick bond » patrick d, patrick b, patrick d.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 moocs optical astronomy sergey ) OR ( the patrick moocs practical astronomy seven ))) OR ((( the patrick mons nautical astronomy sergey ) OR ( the patrick bond nautical astronomy sergey )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( the patrick moocs optical astronomy sergey ) or ( the patrick moocs practical astronomy seven ))) or ((( the patrick mons nautical astronomy sergey ) OR ( the patrick bond nautical astronomy sergey ))))".
• Adding a wildcard symbol may retrieve word variants: (((( the patrick moocs optical astronomy sergey ) or ( the patrick moocs practical astronomy seven ))) or ((( the patrick mons nautical astronomy sergey ) OR ( the patrick bond nautical astronomy sergey ))))*.