SH2-73 (Sharpless 73 ) This object does not do react with any of the narrowband filters, so I do not recommend using H-Alpha on this one. The object does react very well to all the color filters; I would say that red and blue do best. A nice long clear filter image does a very nice job as a luminance image. You need a lot of color data to get really strong color in this one unlike a normal LRGB which uses shorter color exposures. The green will be very weak compared to the red and blue filters. There appears to be a lot of nebula around this object, so a larger field of view may show quite a bit more nebula than is seen here. For a complete list of the Sharpless Catalog visit my main site at http://www.sharplesscatalog.com