Coronado BF-30 30mm Solar Blocking Filter

The Coronado BF30 is a 30mm straight-through type Hydrogen-alpha blocking filter with 2" nozzle. 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 itself 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 3,000mm focal length.

The BF30 is named because of the 30mm clear aperture window that passes the hydrogen-alpha light to the eyepiece or camera sensor. This 30mm window is wider than the window in the BF15, 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 smaller blocking filters.

Note: The BF30 straight-through filter is designed for 2" focusers only. It will not work in a telescope with a 1.25" focuser. Because it is a straight through design, a standard 1.25" diagonal is included in order to convert this BF30 into a right angle design for visual use at a comfortable angle. A foam lined case is also included with cutouts for the filter, diagonal and a small number of optional eyepieces.

Designed and Manufactured in North America.