Sometimes backlighting can work. I've tried having room lights on and off to see if it makes any difference and usually the more light there is the better the camera can handle it... Mucking around with the camera settings can sometimes create some interesting lighting effects that can be a real winner. I always use a tripod, 2 second timer delay and night mode on the camera and it seems to do ok most of the time. Just have to wait for the right flow moments to happen, which is half the fun of course ;)
Here the glow from the fluey seems to be working nicely on the astros - I wrapped the foil around the fluey base to cut down the glare and made a few minor adjustments in iphoto.