Hi Mike,
Just a small correction here... M16 actually refers to the open cluster surronding the eagle nebula. The nebula itself is actually clasified IC4703...
http://www.seds.org/messier/m/m016.html
I know this is real predantic... but I got hammered with this fact last time I showed my image collection to a astro group!!!...
PS.. Loverly images of Mars lately! I am very impressed. Just haven't had much time to post lately, or image lately!
Take care.