Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, optical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy large
moore practical » more practical, moocs practical, mouse practical
astronomy seven » astronomy some, astronomy science, astronomy between

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( the patrick moore practical astronomy sergey ) OR ( the patrick moore practical astronomy seven ))".
• Adding a wildcard symbol may retrieve word variants: (( the patrick moore practical astronomy sergey ) OR ( the patrick moore practical astronomy seven ))*.