i see you've gotten quite a bit of help here, phyllis. good
i'll just throw in that the simplest way, in this image, to bring out the background without altering the helo is to use a contrast/brightness adjustment layer. that's it. that's all you really need. dont adjust the lightness side, just adjust the contrast. i did one set to 0/42 and it looked quite good. this works here because the helo is primarily black with little to have contrasted, so all that apparently changes is the background.
and, if you want a bit more pop to the whole thing, try an S curves in a curves adjustment layer combined with the brightness/contrast layer. i often use these two adjustment layers in sequence to bring some pop to images. it's simple, fast, and adjustable.