Thanks so much for that very thorough response, KathyT!
I was particularly interested in orbs - you can get inexpensive IR cameras for the computer on eBay, I've noticed...
Viking, yes! I've especially heard of Ed Grimsley's work and the type of military grade night vision he uses runs a few grand, I believe - but would be cool to try with something less spendy...couldn't hurt or you can order some through Ed's website.
www.edgrimsley.com