Kieth noted in response to Art's question about driftmeters on Bomber Command
A/C:
Sure but how useful they were on a dark and cloudy night
is another matter.

As long as it was overcast not clouds below, it is/was amazing how much info
you could get from one of those suckers.
One light on the ground or the reflection off of one body of water (pond, lake,
stream) provided something to work with as opposed to nothing.
Gee and H2S were a great improvement to accuracy.
It is one pain in the rear to shoot celestial in an a/c bouncing and bucking
around in Northern European skys.

Rick Clark