observatory vs weather eye

observatory

noun
  • A lookout (vantage point with a view of the surrounding area) 

  • A place where stars, planets and other celestial bodies are observed, usually through a telescope; also place for observing meteorological or other natural phenomena. 

weather eye

noun
  • A device for monitoring the weather. 

  • An ability to detect undercurrents and subtleties in a situation. 

  • An ability to predict short-term weather. 

How often have the words observatory and weather eye occurred in a corpus of books? (source: Google Ngram Viewer )