moonraker vs topgallant sail

moonraker

noun
  • A small, light sail located high on a mast (above the skysail) and used for speed. 

  • Someone from Wiltshire. 

topgallant sail

noun
  • square-rigged sail immediately above topsail -- sometimes divided in two 

How often have the words moonraker and topgallant sail occurred in a corpus of books? (source: Google Ngram Viewer )