Coronado Solarmax III 15mm Blocking Filter - 624016

The Coronado BF15 is a 15mm right angle diagonal type Hydrogen-alpha blocking filter. It includes a long 2" diameter nosepiece with 1.25" eyepiece holder and 42mm t-thread connection.

The BF15 is named because of the 15mm clear aperture window that passes the hydrogen-alpha light to the eyepiece or camera sensor. It provides a full disc image of the Sun for telescopes up to 1500mm in focal length. As the size of the clear window increases (BF30) the larger the field of view and the longer your telescope's focal length can be and still get a full disc image.

The blocking filter is the second element in any Coronado H-alpha system, and is just as crucial to your safety and the system's performance as the primary SolarMax etalon filter, which is not included. The BF15 cannot be used without the etalon in place.