There are two concentric shadows cast by the Earth. The outer is penumbral and the inner is umbral. The umbral shadow is the darker of the two. The eclipse has three distinct phases — penumbral, partial, and total eclipse. The penumbral eclipse starts when the moon begins to enter the penumbral shadow at 9:35 p.m. on Sunday, Jan. 20. You probably won’t notice initially, but by the time the partial phase begins, some graying or darkening will become obvious.