Double umbra (Transcript)
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.