This extremely rare photograph from magazine 42/U was not released by NASA after the mission.
Michael Collins captured this amazing view through the 80mm lens during the third revolution of Apollo 11 around the Moon, showing the deep shadows of the lunar sunset near Crater Engelhardt on the “Dark Side” of the moon. A floodlight on the exterior of the spacecraft is visible in the foreground
From the mission transcript as the spacecraft approached the farside terminator
during the third revolution of Apollo 11 around the Moon:
079:59:17 Armstrong (onboard):
Hey, we're coming up - You can see the horizon… [...]
080:00:58 Collins (onboard):
You're not - you've got plenty of black and white film, don't you?
080:01:01 Armstrong (onboard):
Yes, plenty of black and white film.
080:01:04 Aldrin (onboard):
[Garble] terminator, 4.
080:01:07 Collins (onboard):
Use as much as you want of anything you want. 80 millimeter, 250, it's all good.
080:01:20 Collins (onboard):
We got 20 minutes until TIG. Oh, excuse me, 10 minutes - 10 minutes until TIG, excuse me. A little over 10. 80:11...
080:01:31 Aldrin (onboard):
Give me a call at about 7 minutes to go.
080:01:35 Collins (onboard):
Okay, right now...
080:01:36 Collins (onboard):
080:01:41 Aldrin (onboard):
Yes, siree! That there is rough - rough terrain.
080:01:54 Aldrin (onboard):
I've got kind of an idea that I'm going to be getting a picture of that - [garble].
080:02:44 Aldrin (onboard):
[Garble] all those characters back there.