The SI-HOLA-CIRCLE produces a nine-concentric circle pattern that spans 10 degrees and will reach to the edge of f/ 5.7 optics. Recommended for scopes around this focal ratio or slower. The Laser light is spread over a smaller area it is brighter than the square grid pattern, this makes it particularly useful with Cassegrain scopes, where the pattern impact is sometimes scrutinised on the mirror surface. The projected pattern is seen only by light that is scattered from dust, dirt, or optical roughness, so a brighter pattern is better, especially if the mirrors are very clean.
New Version Howie Glatter Collimators are manufactured with a larger course thread size to facilitate changing the attachments in the dark. Please choose the correct version for your collimator from the drop down list.