The BF-30 Blocking Filter from Coronado is the secondary interference filter in a Coronado H-Alpha solar viewing system. Blocking filters are not stand-alone devices; they must be used in conjunction with a SolarMax filter. In a solar viewing system, the blocking filter is just as crucial to the viewer's safety and the system's performance as the front element.
This 30mm blocking filter, the BF-30, is compatible with telescopes that have a focal length that is equal to or less than 3000mm. It features a 2.0" straight-through design, and a 1.25" zero-length reducer is included.
Note: SolarMax filters are sold in kits that include a blocking filter. This blocking filter offered here is intended for viewers who have two different focal length telescopes that they intend to use with their SolarMax system.
- Must be used with a SolarMax filter
- Image size: 27.2 mm
- 2.0" straight-through design
- 1.25" zero-length reducer included
- For telescopes with a focal length equal to or less than 3000 mm