AstroZap Bahtinov Focus Mask for 14.5" to 17.5" OD Telescopes
AstroZap Bahtinov Focus Masks
Thinly designed lightweight full aperture aluminum focusing mask with modifiable grommets that offers consistently optimal performance. Fits optical tubes with an outside diameter range of between 14.5" and 17.5" (368 mm - 444 mm).
Imagers as well as observers know that to make the most of their valuable telescope time, sharp focus is crucial. In terms of popularity, the Bahtinov-style mask has recently surpassed the Hartmann mask because of its novel diffraction pattern display which enables higher accuracy in determining the optimal focus point. For dark side imagers, where achieving the finest images is reliant upon camera focusing, the Bahtinov mask simplifies the process of finding the ideal focus point so you don't have to estimate anymore. Additionally, quick adjustments can be made when exchanging filters or fixing focus as your imaging session progresses through the night. For light side observers, the Bahtinov mask provides quicker, higher precision focusing, even when switching eyepieces.
AstroZap's Bahtinov Focusing Mask is proudly made in the United States from solid sheet aluminum, unlike the plastic focusing masks offered by competiting manufacturers that don't come close to matching the durability of the former. Powder coating helps protect against corrosion while maintaining its pleasant appearance. AstroZap carries many different focusing mask sizes to fit many of the most popular telescope sizes. Modifiable plastic screws attached to rubber grommets for fixing to the optical tube exterior and keeping it in place to prevent scratching and other damaging to the telescope's finish. Optimal focus is consistently realized with the Bahtinov Focusing Mask's original diffraction pattern display.