The 30mm Blocking Filter is a 2" straight through design and comes with a 1.25" Zero Length reducer. To use, having mounted the narrowband element on the front of the telescope,- simply insert the BF-30 into the 2-inch focuser and put a diagonal plus eyepiece into the rear of the BF-30. CCD or film cameras can be mounted directly into the BF-30 for simple straight through operation.
The Blocking Filter is the second element in any Coronado H-Alpha system, it is just as crucial to your safety and the system's performance as the front element. Use the following guidelines for selecting which Blocking Filter you need based on the focal length of the telescope being used. If you are switching to a longer focal length telescope your SolarMax system you can purchase blocking filters separately.
Focal Length <500mm - BF5
Focal Length <1000mm - BF10
Focal Length <1500mm - BF15
Focal Length <3000mm - BF30
There is no advantage for visual use in using a larger blocking filter than required based on the focal length; however, based on customer feedback, we understand that for imaging with telescopes under 500mm fl, the BF10 is easier to use than the BF5.
The Blocking Filter is not a stand alone filter. It is an integral part of the Coronado design and cannot be used without a SolarMax series filter on the front of the optical system
The BF5, 10, and 15 are all 1.25" right angle diagonals. The BF30 is a 2" straight through design and comes with a 1.25" Zero Length reducer.
May 2003 - We'd like to caution people that you cannot swap Coronado blocking filters and narrowband front elements ad hoc without the risk of compromising safety. On no account, pair a blocking filter from an Isle of Man production run (AS1 series filter) with a US produced SolarMax series filter. The blocking elements have been reconfigured in the newer models and the older blocking filters are NOT compatible from a blocking perspective with the newer front narrowband elements. We can retrofit additional blocking to older blocking filters to make them compatible with newer narrowband elements. We strongly advise anyone considering pairing a front narrowband element with any blocking filter (other than the one it was originally supplied from the factory) to contact customer service. Coronado Components are NOT compatible with any other manufactures H-Alpha systems. Coronado will not be held responsible for problems caused by improper matching of filter elements.