pair of binoculars vs spotting scope

pair of binoculars

noun
  • A hand-held device consisting of a series of lenses and prisms, used to magnify objects so that they can be better seen from a distance, and looked at through both eyes. 

spotting scope

noun
  • A compact high-power monocular telescope optimized for detailed observation of distant objects such as wildlife or the strike of a bullet on a target. 

How often have the words pair of binoculars and spotting scope occurred in a corpus of books? (source: Google Ngram Viewer )