AstroZap Bahtinov Focus Mask for 14.5" to 17.5" OD Telescopes

The AstroZap Bahtinov is a full-aperture focusing mask that is expertly crafted using aluminum for simple, lightweight application. The bahtinov includes adjustable grommets for telescopes with a 14.5" - 17.5" (368 mm - 444 mm) outer diameter. The thin construction allows for optimal performance.

All observers and imagers are aware of the fact that sharp focus is necessary for making the most out of your valuable time with the telescope. The Bahtinov-style mask has now passed the Hartmann mask in popularity due to its novel diffraction pattern that enables higher accuracy for detecting the ideal focus point. For observational light side astronomy, the Bahtinov mask allows quicker, more exact focusing when switching eyepieces. For imaging (dark side astronomy), where camera focusing is crucial to achieving the finest images, the Bahtinov mask makes it easy to find the point of optimal focus without having to guess and enables quick adjustments when switching filters or fine-tuning focus as your imaging session persists into the night.

The Astrozap Focusing Mask is proudly made in the United States from solid sheet aluminum, contrary to plastic focusing masks available from other manufacturers that are not anywhere near as durable. Powder coating helps maintain its appealing looks by preventing corrosion. AstroZap carries several sizes of focusing masks to fit telescopes with the most common outside diameters. Plastic screws mounted in rubber grommets are adjustable in order to conform to the exterior of the optical tube, keeping the screen in place while avoiding scratching or otherwise causing harm to the telescope's finish. The unique Bahtinov diffraction pattern utilized by this AstroZap Focusing Mask enables consistently optimal focus.