Azimuth.

I have studied astronomy my entire life, and I am aware of no other common term for it than "lunar eclipse" or perhaps "eclipse of the moon".

A lunar distance is equivalent to the distance from the Earth to the Moon which is approx. 384,000km. So to convert lunar distances to km, just multiply the lunar distance by 384,000.

In this case .85*384,000 = 326,400km.

And if you're referring to Asteroid 2005 YU55, then it will pass closer to us than the Moon does.

for determining distance

Astronomy is the study of the sun, moon, stars, planets, galaxies and other things in space. An eclipse involves the sun and the moon, whether it is a lunar or solar eclipse, so they are related to astronomy.