Optolong OIII 6.5nm Narrowband Filter 36mm Unmounted (OPT-OIII-65NM-36MM) Manual Mount Housed in a 2" barrel

Housed in a 2" barrel like the 35mm

For a bit more than generic brands

Easy to use in the field

put M-13 at the edge of the field and enjoy fully resolving its beauty as it drifts across your view

Internal hard stops for both axes prevent cable tension and tripod strike

Optolong OIII 6.5nm Narrowband Filter 36mm Unmounted (OPT-OIII-65NM-36MM) Manual Mount Housed in a 2" barrelOptolong improved extra Narrowband OIII CCD 6. 5nm filter is designed for nebula observation allowing 6. 5nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission lines, and reducing the transmission of certain wavelengths of light, specifically those produced by artificial light including mercury vapour, and both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral