The light emitted by a light source, like any other opaque object, casts shadows from the moon and earth into space. Each shadow has 3 different regions: amber, penumbra, and antumbra.
Umbrella / amber is the dark core of the shadow. Imagine a light source and an object casting a shadow. If you are standing under an umbrella, you will not be able to see any of the light sources as the object blocks out all direct light rays.
The lunar eclipse causes total solar eclipses, and the Earth’s umbrella is part of a full or partial lunar eclipse.
The penumbra is a half-shadow that occurs when a light source only partially covers an object
The Moon’s penumbra causes partial solar eclipses, while the Earth’s penumbra includes penumbral lunar eclipses.
Antumbra is the lightest area of the shadow visible beyond the umbrella, at a certain distance from the shadow casting object. It only exists if the light source has a larger diameter than the object. It is involved in annual solar eclipses and planetary transits.
In Antumbra, you see the outside of the light source around the shadow casting object. For example, if you were in Antumbra during an annual solar eclipse, the tip of the Sun’s disk would appear as a “ring of fire” around the Moon.