spotting scope vs theodolite

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. 

theodolite

noun
  • A surveying instrument, consisting of a small mounted telescope, used to measure horizontal and vertical angles. 

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