Askar Duo-Band 3 nm 2" is a professional astronomical filter from the Askar Color Magic series, dedicated to photographing such objects as emission and planetary nebulae, or remnants of supernova explosions.

This filter is characterized by transmission at the level of 88% for lines of spectral lines emitted by ionized hydrogen (Hα) and oxygen (OIII) atoms. Combined with the efficient cut-out of spectral lines characteristic of sodium and mercury lamps, it allows you to record sharp and contrasting images even near large cities or during bright, moonlit nights. The filter has a very narrow half width of the pass bands, only 3 nm, thanks to which it allows to obtain a much better contrast and a much darker background than in the case of two-band filters with a wider transmission window.

The filter is equipped with a standard, two-inch frame, and the set includes a dedicated protective box that facilitates safe transport and storage.

The most important features of the Askar Duo-Band 3 nm 2" filter

• dual band high transmission filter for Hα and OIII lines
• half-width of the passbands at the level of 3 nm
• very high efficiency of light pollution removal

Technical parameters

• filter type: two-band filter
• Filter diameter: 2"
• filter thickness: 1.85 ± 0.05 mm
• half bandwidth (FWHM): 3 nm
• pass bands: Hα, OIII
• maximum transmission: 88%
• blocking range: 200 - 1100 nm
• optical density equivalent for blocking range: >OD5
• surface quality index: 60/40
• parallelism: 30"

Set elements

• Askar Duo-Band 3nm 2" filter

Guarantee

24 months