Coronado SolarMax III Blocking Filter BF30

Coronado SolarMax III Blocking Filter BF30

£2,199.00✓ 2 year warranty


Out of stock due 15-20 working days

About this product

Model:  coronado_solarmaxIII_bf30
Part Number:  624017

Coronado SolarMax III Blocking Filter BF30

The Coronado BF30 30mm right angle (diagonal) type Hydrogen-alpha blocking filter, now in the SolarMax III design.

This updated design includes a long 2" diameter nosepiece with a 1.25" eyepiece holder and a T-thread connection. The 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. This secondary interference filter provides a full disc image of the Sun for telescopes up to 3,000mm focal length. 

NOTE: This blocking filter CANNOT be used itself without a SolarMax etalon in front of the telescope front aperture. 

This 30mm blocking filter is a convertible design and ideal for imaging the sun! Convert from the 1.25" right angle configuration to a 2" straight design with the included straight-thru adapter. It also includes Coronado's zero-length 2" to 1.25" adapter, so you can use all your favourite 1.25" accessories.

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 when compared to smaller blocking filters. And because of the versatility of converting this BF30 to a straight-through design with the included adapters, this is the best blocking filter in Coronado's line for the largest variety of camera sensors and wide apparent field of view eyepieces.

Note: The BF30 cannot be used with the #624018 Coronado 1.25" nosepiece adapter as BF30 filters are in the 2" nosepiece. The BF30 is the only blocking filter in the Coronado BF line that has filters in the 2" nosepiece section to allow it to convert to straight-through mode.

Designed and Manufactured in North America.


  • Hydrogen-alpha blocking filter for Coronado primary etalon filters
  • Secondary interference filter for full disc image of the Sun for telescopes up to 3,000mm focal length
  • Coronado's largest blocking filter, with a long 2" diameter nosepiece with 1.25" eyepiece holder and t-thread
  • Can convert to straight-through mode with included 2" straight-through adapter for more versatility with cameras and other 2" accessories

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