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 65 of 80 
Orion Telescopes
Coronado SolarMax III Blocking Filter BF30
3 easy payments of $766.66
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  • 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 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
  • MUST be used in conjunction with a front etalon filter - cannot be used alone

Learn more
Item #  55897b
Mfg Model #  624017

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 1.25" eyepiece holder and 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. 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.

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. Also includes Coronado's zero-length 2" to 1.25" adapter so you can use all your favorite 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 compared with the 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, in order to allow it to convert to straight through mode.

Designed and Manufactured in North America.

Product Support
Visit our product support section for instruction manuals and more

Blocking Filter
2" Straight through adapter
Zero length 2"-1.25" adapter
SMIII 70mm instruction manual

Orders received by 1pm Eastern Standard Time for in-stock items ship the same business day. Order received after noon will ship the next business day. When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available. You have the option in check out to request that your order ship complete, if you'd prefer.

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