It's worth pointing out this little bit of text, which I just found right at the bottom of the NPB page.....
"© 2006 Omega Optical, Inc
Note: Images on this site were acquired through NASA's Hubble Space Telescope WFPC
using Omega Optical's filters and are used here courtesy of NASA's
Jet Propulsion Laboratory"
Although lesser known than the Astronomiks, etc, names in amateur astro filter circles, obviously the guys at Omega Optics know their stuff.