refracting telescope vs spyglass

refracting telescope

noun
  • A telescope which produces a magnified image by refracting light through a series of lenses housed in a tube, with a light-gathering objective lens at one end and an eyepiece at the other. 

spyglass

noun
  • A pair of binoculars. 

  • A small portable telescope. 

How often have the words refracting telescope and spyglass occurred in a corpus of books? (source: Google Ngram Viewer )