Optolong OIII 3nm Filter Size:36mm Glass Only 25 inch design also offers

25 inch design also offers the shortest possible backfocus

For 6nm MaxFR filters: Unrestricted usability from f/2

The UHC-E Filter increases the contrast of emission nebulae and comets and blocks the light of typical streetlights as well as airglow

With a 76mm aperture and a focal length of 418mm

Optolong OIII 3nm Filter Size:36mm Glass Only 25 inch design also offersOptolong OIII 3nm Ultra Narrow Band Deep Sky Imaging Filter for CCD CMOS Astro Photography Here below you will find a description of all three types of filters for your information as a full bundle is also available, however this product listing is only for the Optolong 3nm OIII filter. Please note, if you buy the full HSO bundle you will save some money in comparison to the price of the individual items. General Product Description for All Versions