Coronado BF5 - 5mm Blocking Filter

Coronado BF5 - 5mm Blocking Filter
Item # CI-BF5
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  • The Coronado BF5 5mm Blocking Filter is designed for telescopes with focal lengths of up to 500mm.
  • You must pair the BF5 with a Coronado Solarmax series narrowband element front.
  • The Coronado BF5 5mm Blocking Filter provides full disc images.


Coronado BF5 - 5mm Blocking Filter

The Solarmax series filters come in two parts, the front narrowband element (sold separately) and a secondary interference filter which mounts at the eyepiece end of the telescope. You cannot use the individual units separately. If you do not have a SM40, 60, or 90 or a T-Max tuner, it will be more economical to purchase them as a package. Otherwise, choose the secondary blocking filter based on the focal length of your telescope.

The Coronado BF5 - 5mm Blocking Filter provides full disc images on telescopes with less than 500mm of focal length. If you have any questions, please contact OPT, and we will help you put together the correct system for your telescope. Please note the photo above shows a collection of different blocking filters. The BF5 is mounted in a 1.25" right-angle star diagonal.

Safety is the most important consideration when doing solar observing of any type!

Here are some important considerations if you are putting together a system made from older parts or those of unknown origin:

Coronado Instruments would like to caution people that you cannot swap Coronado blocking filters and narrowband front elements ad hoc without the risk of compromising safety. Never 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 US produced models and the older, Isle of Man blocking filters are NOT compatible from a blocking perspective with the newer front narrowband elements. Coronado can retrofit additional blocking to older blocking filters to make them compatible with newer narrowband elements. They 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 OPT to determine if additional blocking is required. Coronado Instruments and OPT will not be held responsible for problems caused by improper matching of filter elements.

Coronado Instruments Product Number: BF5

Additional Information

Additional Information

Manufacturer Coronado
Solar Accessory Type Filters
Warranty 1 Year Warranty
Included Items

Included Items

  • Coronado BF5 - 5mm Blocking Filter
  • 1.25" Diagonal Mount
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