The B600, B1200, B1800 and B3400 blocking filters from Lunt Solar Systems are essential components for safe H-alpha observation of the Sun. They are fitted to the eyepiece end of the telescope and are designed for use with a compatible Lunt h-alpha etalon filter system. The integrated filter components suppress unwanted radiation and, in conjunction with the etalon, enable high-contrast observation of the solar chromosphere with its filaments, prominences, flares and active regions.
Four filter sizes for different focal lengths and applications
The model designation indicates the clear filter aperture in hundredths of a millimetre: the B600 has an aperture of 6 mm, the B1200 of 12 mm, the B1800 of 18 mm and the B3400 of 34 mm. A sufficiently large clear aperture is crucial to ensure that the image of the Sun can be captured in its entirety without any distracting edge shading.
- B600: For visual observation with telescopes with focal lengths up to approximately 600 mm; for photography, up to 400 mm. Particularly suitable for compact instruments with short focal lengths.
- B1200: For visual observation with focal lengths up to approximately 1,200 mm, and for photography up to 600 mm. A versatile solution for numerous small and medium-sized telescopes.
- B1800: For visual observation with focal lengths up to approximately 1,800 mm, and for photography up to 1,200 mm. The larger aperture offers additional headroom for longer focal lengths and photographic applications.
- B3400: For visual observation with focal lengths up to approximately 3,400 mm. With its particularly large clear aperture, it is suitable for long-focal-length telescopes, large-format camera sensors and the use of a binocular head. For solar photography, Lunt recommends this filter for focal lengths up to approximately 1,800 mm.
Of particular interest for demanding photography: the B3400
The B3400 occupies a special position within the product range. Its 34 mm clear aperture provides a particularly large passage for the light cone, offering plenty of scope for the use of larger camera sensors. Even in optical configurations requiring a greater back focus, the larger aperture can help to prevent vignetting. The B3400 is housed in a straight 2-inch extension tube with 2-inch and T2 mounts. Unlike the smaller variants, it is not available as a diagonal mirror.
Flexible integration into the H-alpha system
The B600, B1200 and B1800 models are available, depending on the version, in a 90° diagonal mirror or a straight extension tube. Different mounting diameters and camera connections allow adaptation to various telescopes and imaging devices. The B3400 is intended for straight installation only.
Please note: Blocking filters are not standalone solar filters. They must never be used on their own for solar observation. A compatible Lunt h-alpha Etalon filter system is required for safe operation. The components must be combined in accordance with the manufacturer’s specifications.
