Perhaps you should try some spelling variations:
practical astronomy » nautical astronomy, positional astronomy
optical astronomy » nautical astronomy, spherical astronomy, positional astronomy
astronomy series » astronomy sergey, gastronomy services, astronomy survives
does practical » notes practical, does practice, globes practical
patrick does » patrick dobel, patrick de, patrick del
patrick main » patrick mein, patrick cain, patrick kain
main optical » domain optical, ion optical, non 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 does practical astronomy series ) OR ( the patrick main optical astronomy series )).
• Adding a wildcard symbol may retrieve word variants: (( the patrick does practical astronomy series ) or ( the patrick main optical astronomy series ))*.