Coronado BF15 15mm Solar Blocking Filter

The Coronado BF15 15mm 1.25" right angle (diagonal) type Hydrogen-alpha blocking filter is designed to sit behind a SolarMax etalon to provide beautiful H-alpha views of the Sun. This 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. Note this blocking filter CANNOT be used without a SolarMax etalon in front of the telescope front aperture. This secondary interference filter provides a full disc image of the Sun for telescopes up to 1,500mm focal length. Designed to be used with telescopes with a 1.25" focuser opening, and accepts 1.25" eyepieces and camera nosepieces on top. For use on a 2" telescope focuser, consider the #624016 SolarMax III BF15 version.

The BF15 is named because of the 15mm clear aperture window that passes the hydrogen-alpha light to the eyepiece or camera sensor. This 15mm window is wider than the window in the BF10, and thus provides a wider unvignetted field of view around the sun. This will allow wider apparent field of view eyepieces, higher magnification, and larger camera sensors to see an unvignetted view compared with the BF10 version.

Designed and Manufactured in North America.