Orion 1.25" Extra-Narrowband Tri-color CCD Filter Set Shoot high-contrast color CCD images of emission nebulas from light polluted or moonlit skies with these specialized astrophotography filters Filter Set includes three dichroic, 1.25" extra-narrowband astrophotography filters: H-alpha, O-III, and S-II, all with metal filter cells These filters transmit specific wavelengths emitted by emission nebulas and block all other light -including light pollution - so you can capture astrophotos in less than ideal conditions Each Orion Extra-Narrowband filter features 90% transmission at the specified critical wavelength and a narrow 7nm bandpass (FWHM) for great results Ideal for use with monochrome Orion StarShoot and Parsec astrophotography cameras to acquire stunning tri-color vistas of the night sky