Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, positional astronomy
optical astronomy » nautical astronomy, spherical astronomy, positional astronomy
astronomy sergey » astronomy survey, astronomy surveys, astronomy large
astronomy seven » astronomy some, astronomy science, astronomy between
mkie practical » more practical, made practical, make practical
moore optical » moire optical, core optical, moon optical
patrick mkie » patrick mackie, patrick mein, patrick m
patrick more » patrick moyes, patrick mark, patrick marx
more optical » moire optical, core optical, more optimal

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 mkie practical astronomy sergey ) OR ((( the patrick moore optical astronomy seven ) OR ( the patrick more optical astronomy seven )))).
• Adding a wildcard symbol may retrieve word variants: (( the patrick mkie practical astronomy sergey ) or ((( the patrick moore optical astronomy seven ) or ( the patrick more optical astronomy seven ))))*.