American Experience
TeamworkVisual ObservationsThe Apollo 8 Mission
The moon below (0:17)

Shooting Earth rise (1:46)

Double umbra (0:44)

Where are we? (0:21)

Double umbra (Transcript)
December 24, 1968 -- Day 4

Borman: I won't be able to get a boresight star because we'll be in the daylight.

Anders: What about Jim?

Borman: Well, I don't know; I hope he can. Are you going to do that before we press on, Jim?

Anders: When we get --

Lovell: Why don't I just set --

Anders: ...your double umbra, why, you can do it then.

Lovell: What's this double umbra?

Anders: Double shadow. When the earth sets, then you will be able to -- you'll be looking at 90 degrees back and you can look right down on it.

Lovell: When the earth sets?

Anders: Yes, the umbra is the shadow.

Lovell: Oh, yes, okay.

Anders: So we're in the shadow of the sun; that's the umbra of the moon, and when we're in the shadow of the earth, that's the umbra.

Race to the Moon American Experience PBS