Lunt B1800s Blocking-Filter in extension tube

Lunt H-alpha Blocking Filter - B1800s

Blocking Filter in straight extension tube, for telescopes up to 1620mm focal length. Can only be used together with a Lunt H-alpha filter!

Lunt Solar Systems currently offers 4 blocking filter apertures for use with our H-alpha Etalon systems. The Blocking Filter are absolutely required for the safety and performance of telescopes for solar observing! Blocking filter will be mounted at the eyepiece-side of the telescope, and protect against the dangerous radiation from the sun.

We are currently offering the B600d, B1200d, and B1800d in a 90° star-diagonal, with 1.25" or 2" on the telescope side, and T2 (M42x0.75) and 1.25" on the eyepiece side.

The B600s, B1200s, and B1800s is also being offered in a straight thru extension tube with T2 on both sides, 1.25" and 2" on the telescope side, and 1.25" on the eyepiece side. The extension tube of the B3400s has a 2" connection on the telescope side, and a 2" eyepiece reception and adapter for 1.25" eyepieces on the other side.

The Blocking Filter B600 is for maximum focal length 540mm, B1200 is for 1080mm, B1800 is for 1620mm and the B3400 is for 2880mm maximum focal length. This is the focal length of telescope for which that particular blocking filter will provide a full disk image of the Sun. A blocking filter larger than that required is needed for imaging.

Lunt Solar Systems blocking filters contain a unique filter system. We can only warranty safety or performance when blocking filter is paired with a H-alpha filter of Lunt Solar Systems.