first light vs sunlight

first light

noun
  • The time when light first appears in the morning; dawn, especially the start of dawn. 

  • The first use of a telescope or other instrument to capture an astronomical image. 

sunlight

noun
  • Synonym of sunrise. 

  • All the electromagnetic radiation given off by the Sun, especially that in the visible spectrum that bathes the Earth. 

  • Brightness, hope; a positive outlook. 

verb
  • To work on the side (at a secondary job) during the daytime. 

How often have the words first light and sunlight occurred in a corpus of books? (source: Google Ngram Viewer )