Perhaps you should try some spelling variations:
practical astronomy » positional astronomy
optical astronomy » spherical astronomy, positional astronomy
astronomy surveys » astronomy survey, astronomy surveying, astronomy survives
astronomy sergey » astronomy survey, astronomy large, astronomy society
moocs practical » books practical, mics practical, colts practical
astronomy seven » astronomy some, astronomy science, astronomy between
moocs nautical » hoc nautical, logs nautical, nos nautical
patrick moocs » patrick moore, patrick mons, patrick moyes
moocs optical » moon optical, topics optical, cmos 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 moocs practical astronomy sergey ) OR ( the patrick moocs optical astronomy sergey ))) OR ( the patrick moocs practical astronomy seven ))) OR ( the patrick moocs nautical astronomy surveys )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((((( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs optical astronomy sergey ))) or ( the patrick moocs practical astronomy seven ))) or ( the patrick moocs nautical astronomy surveys ))".
• Adding a wildcard symbol may retrieve word variants: (((((( the patrick moocs practical astronomy sergey ) OR ( the patrick moocs optical astronomy sergey ))) or ( the patrick moocs practical astronomy seven ))) or ( the patrick moocs nautical astronomy surveys ))*.