Filter ANTLIA ALP-T Dual Band (SII - HB) 5nm model 50.8mm

All you need to know about the Antlia ALP-T Dual Band 5nm filter

The Antlia ALP-T Dual Band 5nm filter is designed for use primarily with color sensors for single shot color (OSC) imaging, such as color astronomical cameras or digital still cameras. It can also be used as a narrow band filter in monochrome cameras to save imaging time.

The advanced multi-coatings of the ALP-T ultra-dual band filter effectively isolate H-alpha red light and OIII blue-green light from emission nebulae, with near-total suppression of optical density (OD) 4.5 at unwanted wavelengths from light pollution, moonlight and sky light. As a result, the 5 nm dual-band ALP-T filter creates a superior signal-to-noise ratio and better contrast in your images.

This filter allows capturing the 2 main emission bands of nebulae at the same time, while suppressing unwanted signals. As a result, the raw images are cleaner and require less post-processing. Because the Antlia ALP-T 5 nm dual-band filter looks golden yellow to the naked eye, it is also called a "golden filter".

Transmission curve of the Antlia 5 nm dual-band filter. The wavelength in nanometers is on the abscissae. The transmission percentage is on the ordinate. The transmission width at half height is 5 nm and the filter is centered at 500.7 nm and 656.3 nm.

Applications and performance

• Designed specifically for use with DSLR, CMOS and color CCD cameras. Optical Density (OD) 4.5 suppression at unwanted visual wavelengths increases the signal-to-noise ratio
• Sharp cuts on extremely steep lines minimize internal reflections
• Ion gun-assisted deposition coating technology on the double-sided polished substrate, making it the most consistent and accurate light pollution suppression filter on the market
• Good performance at focal ratios above F/3, with contrast increasing with focal ratio
• Designed to suppress artificial illumination from Bortle scale 1 to 8. Near IR (NIR) is blocked up to 1100 nm

Technical Specifications:

• Mounting diameter 36mm circular casting, unmounted
• Substrate thickness 2mm
• Transmission 90% transmission on H-alpha line 656.3nm
• 82% transmission on O-III line 500.7nm
• Treatments Filter polished on 2 sides with λ/4" accuracy
• Multilayer and anti-reflective coating on both faces