[turbine]

Pretty much covered in above post except that I know some optics are filled with a gas which creates somewhat of a green hue, especially at night and create an optical effect of hi-lighting the edges of the viewed environment. Not real night vision. I owned a set of bino's a few years ago when I was in the army and they worked real well. The type of gas they were filled with escapes me now and I have been unable to search it out.