Gerd Neumann Bahtinov Mask for 49mm Filter Thread
Made to fit the 49mm filter threads of your photographic lens, using a Bahtinov mask by Gerd Neumann is quick and easy. If you're a DSLR or SLR astro-photographer, you need this accessory!
Perfect focus is extremely important, particularly for the astrophotographer. Even a slight digression from perfection can result in blurry or lopsided stars. Out of all of the focusing tools available on the market, often times the best ones are the most simple. The Bahtinov mask, named after its creator, Pavel Bahtinov, is a grid that is placed over the front of your telescope or lens. A specialized pattern of straight slots, running parallel to one another creates a helpful pattern of bright spikes that will radiate out from a focus star. You know you are in focus when those spikes meet at their center and form a symmetrical star-burst type shape.
Gerd Neumann's Bahtinov masks use a very large number of slots compared to other masks allowing much more light to reach your camera sensor therefore allowing you to use a larger array of stars for focusing. On a very bright star and while using a DSLR in live view mode, you can focus very easily. Simply attach the mask to the front of your lens, aim yourself at a bright star of your choosing, turn your camera on and go into a live view mode. Focus until you've achieved a symmetrical pattern and remove the mask. You're now ready to capture a perfectly focused image!
GNJ Bahtinov masks are made from black coated aluminum to maintain a light weight but lasting durability with the ability to be threaded directly into a photographic lens. Unlike homemade cardboard masks, pattern edges stay sharp and intact and are precision-laser cut.