M16 Eagle H-a/OIII

This is a combination of H-a taken by Ken Crawford on a 20" RCOS RC with a Yankee Robotics Trifid camera using Astrodon 6 nm H-a filter in Camino, CA and by Don Goldman on a 16" RCOS Aries RC with an SBIG STL11000 and the same H-a filter at New Mexico Skies.  Special procesing in Photoshop CS was used assigning OIII to Blue, H-a to Green and another layer where just the highlights of the H-a image were mapped to orange to simulate a mixture of SII and H-a.  The brigher regions of H-a images in nebula commonly seem to be the most pronounced areas in the SII images.  So, this was an attempt to synthesize an SII layer.