Chuck, I use an OIII filter for the Veil, NGC 6888, North American nebula, Thor's Helmet, and the Rosette nebula. Last summer, the Cacoon nebula and Abell 39 looked good with my UHC filter. Most of the brighter emission nebulae benifit from the UHC filters. Most of the time, I use my OIII filter for faint planetary nebulae, although the Ring and Dumbell planetaries I observe with the UHC or no filter at all. So if I'm in the city and I'm looking at planetary nebulae, I use my OIII filter. By the way, I have a whole list of planetary nebulae observable from the city if anybody is interested. I also like the UHC on the Orion nebula although it looks green with the filter and blue without it. Debbie