I was searching old posts on ME and remembered some was mentioning when u shoot night scenes, do multiple exposures for foreground (or moon) and background, or something like that. Then I chanced on mervlam's post

"2) use multiple exposure. expose the moon at the inverse of the ISO speed of the film at f/16 first. eg ISO 400 film at 1/400s with f/16. then superimpose the buildings on the dark areas. be careful not to overlap the moon."

Can some1 iterate?