Corona detector with narrow-band optical filter

Abstract

A corona detector for detecting a corona associated with a remote object. In one embodiment, the corona detector employs an optical filter having at least one passband centered at a wavelength corresponding with one of the molecular nitrogen emission spectrum second positive emission lines in the visible spectrum for filtering light from the remote object. A lens operatively coupled to the optical filter forms an image of the remote object, the lens having high transmissivity in the visible spectrum.

Dependencies are inferred from the claim text.