Published in Sky and Telescope, October, 2005, page 122.
Published in Astronomy, January, 2006, page 118.
6 nm Astrodon H-a, OIII. OIII mapped as teal. H-a mapped as red in clipped layer masks
H-a image:
Image Date: 06/11/2005 Details: Exposure Time: 3 hrs Total; 1.5 hrs H-a, 1.5 hrs OIII Camera: SBIG  STL11000 Telescope: RC Optical  Carbon Truss 12.5 inch f/9 Ritchey-Chretien Mount: Software Bisque  Paramount ME