SHO Filters | Astronomy Filters | 1.25″, 36 mm & 2″

The precise narrowband design effectively suppresses background noise while highlighting the emission structures of different elements, resulting in clearer celestial stratification and enhanced detail gradation.

▲ Hα filter: Central wavelength 656.3nm, FWHM 3.5nm.
Optimized for hydrogen ionization regions, this filter serves as the primary channel for capturing nebular morphology.
▲ OIII filter: Central wavelength 500.7nm (OIII emission line), FWHM 4nm.
Designed to reveal high-energy excitation zones, particularly effective for visualizing blue-green nebular details.
▲ SII filter: Central wavelength 671.6nm, FWHM 4nm.
Enhances detection of faint signals and reveals structural stratification through ionized sulfur distribution. When combined with Hα, significantly improves image contrast.
*FWHM for 1.25-inch and 2-inch filters is 6.5nm.

The entire series of ToupTek Astro filters utilize high-quality colorless transparent quartz glass, with >90% high transmittance, high purity, exceptional blue-violet band transmission, and outstanding thermal stability—ideal for various demanding astronomical imaging applications.

Using IAD (Ion Assisted Deposition) coating technology, which is more costly than conventional vacuum evaporation but produces denser and more uniform coatings that are durable, corrosion-resistant, and have superior environmental stability.

ToupTek Astro filters employ a proprietary multi-layer system: a single-sided cutoff coating, front surface AR anti-reflection coating, and edge blackening treatment. This combination effectively minimizes internal reflections and stray light while ensuring coating integrity and extended service life.

All channel filters have a cutoff depth of OD≥5.0, effectively blocking non-target spectral regions, avoiding band crosstalk and color cast, resulting in accurate and natural color reproduction.

The filter edge is coated with a black matte treatment to minimize stray light, which ensures transmittance, reduces glare, and enhances image contrast.
▲ 36mm filters: The telescope-facing side has an inward-extending blackened border for quick orientation identification.
▲ 1.25" & 2" filters: Feature threaded aluminum alloy frames for direct screw-in installation, ensuring fast and tool-free mounting.

All filters use a single-piece, glue-free structure.
▲ 36mm: Recommended for APS-C and smaller cameras.
▲ 1.25": Recommended for cameras with a 1-inch or smaller sensor.
▲ 2": Recommended for full-frame and smaller cameras.
Compatible with various brands on the market featuring 7-hole 36mm, 8-hole 1.25-inch, and 5-hole 2-inch electric filter wheels, offering a wider range of compatibility options.