Antlia S-II 2 2,5 nm Ultra narrowband filter all astro filters opinie

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Antlia S-II 2" 2.5 nm Ultra is a professional astrophotography filter with a half-transmittance window width (FWHM) of 2.5 nm. It transmits light with a wavelength of 672.4 nm emitted by doubly ionized sulfur atoms, the registration of which is particularly important when photographing emission nebulae.

This filter combines the ability to almost completely eliminate the unwanted component coming from sodium and mercury lamps with high transmittance for the S-II spectral line, one of the most important from the point of view of astrophotography . It was made on a high-quality quartz glass substrate characterized by increased resistance to damage and increased thermal stability.

Antlia S-II 2" 2.5 nm Ultra is distinguished by a steep course of the slopes of the transmission window and a flat course of the transmittance curve. Carefully selected spectral characteristics make the filters from the 2.5 nm Ultra family ideal for cooperation with telescopes with a wide range of light intensity, including bright OTAs down to f/3.5.

Attention! The S-II filter is not recommended for visual observation or solar observation.

Highlights of the Antlia S-II 2" 2.5 nm Ultra filter

• bandpass filter made on a high-quality optical substrate with maximum transmission for radiation with a wavelength of 672.4 nm
• substrate made of quartz glass with excellent thermal stability and high mechanical strength
• compatible with astrographs with light intensity up to f/3.5 while maintaining minimal signal loss
• half-band width (FWHM) of 2.5 nm
• optical density equivalent OD5 guaranteeing high efficiency of light pollution removal

Technical parameters

• filter type: bandpass filter
• substrate: quartz glass
• Filter diameter: 2"
• filter thickness: 2 ± 0.05 mm
• filter shape: round
• pass bands: S-II (672.4 nm)
• location of the peak of transmittance (CWL): 672.4
• half bandwidth (FWHM): 2.5 +0.3 nm / -0.1 nm
• maximum transmission: >95%
• blocked light pollution bands: mercury lamps (435.8 nm, 546.1 nm, 577 nm, 578.1 nm), sodium lamps (598 nm, 589.6 nm, 615.4 nm, 616.1 nm)
• optical density equivalent for blocked lines: OD5
• holder thread: M48x0.75

Set elements

• Antlia S-II 2" 2.5 nm Ultra filter

Guarantee

3-year manufacturer's warranty (for delamination of the filter and substrate)