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    ToupTek Astro

    SHO Filters 4nm 2inch

    SHO Filters 4nm 2inch

    $219.00 USD
    $219.00 USD
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    Description
    REVIEWS

    SHO-2-inch-4nm

    Precision Narrowband Filter

    ToupTek Astro SHO Narrowband Filter Introduction

    Narrowband filters are essential for astrophotography. The ToupTek Astronomy SHO filter targets the three key ionized emission lines in stellar nurseries: Hα, SII, and OIII. With a narrower 4nm FWHM bandpass, it precisely transmits the target light while providing stronger suppression of urban light pollution and background gradients. This also reduces band overlap, resulting in higher signal-to-noise ratio, improved contrast, and more distinct detail. It is well-suited for creating images in the Hubble Palette.

    SHO Filter Product

    Technical Parameters

    Size 2"
    Glass Thickness 2mm
    Transmittance ＞90%
    FWHM H-alpha (4nm) / SII (4nm) / OIII (4nm)
    Glass Material Quartz glass
    Frame Material Aluminum Alloy
    Coating Technology IAD (Ion Assisted Deposition)
    OD ≥5.0

    Transmission Range:

    ▲ H-alpha filter: Central wavelength 656.3nm
    ▲ SII filter: Central wavelength 671.6nm
    ▲ OIII filter: Central wavelength 500.7nm
    Filter Details

    Spectrum Analysis

    Spectrum Chart

    Spectral Chart Reading Tips:

    • The horizontal axis represents the wavelength of light (in nm), and the vertical axis represents the light transmittance (in percentage %). The red line indicates Hα (656 nm), the green line indicates OIII (500.7 nm), and the blue line indicates SII (672.4 nm).
    • The emission nebula signal bands are mainly concentrated around 656nm (Hα), 500.7nm (OIII), and other bands.
    • Light pollution peaks are commonly found near 540nm and 590nm (sodium lamp/mercury lamp bands).
    • The transmission regions avoid major interference bands to ensure effective signal passage, enhancing contrast and image purity.

    Key Features

    Precise Band Control, Enhanced Detail Resolution

    Precise narrowband filters suppress background noise while highlighting elemental emission structures, revealing celestial stratification and fine details.

    ▲ Hα (656.3nm | 4nm FWHM): Optimized for hydrogen regions; primary channel for nebular morphology.
    ▲ OIII (500.7nm | 4nm FWHM): Targets high-energy zones; reveals blue-green nebular details.
    ▲ SII (671.6nm | 4nm FWHM): Enhances detection of faint signals; Significantly boosts contrast when combined with Hα.

    High-Quality Quartz Glass

    ToupTek filters feature high-purity quartz glass substrates with >90% transmittance. They deliver exceptional blue-violet transmission and thermal stability, ideal for demanding astronomical imaging.

    IAD Dense Coating

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

    Precision Coating

    ToupTek filters use a proprietary multi-layer coating system—including single-sided cutoff, front AR coating, and edge blackening—to eliminate halos, minimize stray light, and ensure long-term durability.

    High Optical Cutoff Depth

    All filters feature OD≥5.0 cutoff depth, blocking unwanted light to eliminate artifacts and deliver true-to-life color reproduction.

    Matte Black Edge Coating

    All filters feature matte black edge treatment to eliminate stray light, ensuring optimal transmittance and contrast. 2" filters feature threaded aluminum alloy frames for direct screw-in installation.

    Highly Compatible

    All filters use a single-piece, glue-free structure. 2": Full-frame & smaller sensors. Compatible with industry-standard filter wheels: 2": 5-hole/ 7-hole

    Performance Gallery

    IC5070 Astrophotography

    IC5070

    Photographer: voice | Telescope: Sky-Watcher | Mount: UMI
    Camera: ToupTek Astro ATR2600M | Filters: ToupTek Astro LRGB&SHO
    Integration: Hα: 30 x 600s; SII: 30 x 600s; OIII: 30 x 600s
    Total exposure: 15h
    IC 443 Astrophotography

    IC 443

    Photographer: voice&免贵姓姚 | Telescope: Sky-Watcher F3.4
    Camera: ToupTek Astro ATR2600M/ATR2600C | Mount: UMi
    Filters: ToupTek Astro SHO 4nm
    Processing: Narrowband combination using HSO channel mapping
    Total exposure: 20h
    NGC2237 Astrophotography

    NGC2237

    Photographer: 原上行川 | Telescope: Askar SQA55
    Camera: ToupTek Astro ATR2600M | Mount: iOptron HAE16C
    Filters: ToupTek Astro SHO | Astrophotography wireless controller: StellaVita
    Integration: Hα:71, OIII: 63, SII: 49
    Total exposure: 15h

    Installation

    Screw directly into filter wheels—no front/back orientation needed.

    Installation Guide

    Warranty and Service

    Quality Assurance

    Each filter undergoes pre-delivery spectral testing and rigorous screening to ensure consistent optical performance.

    After-sales Policy

    A two-year warranty covers manufacturing defects. ToupTek Astro offers professional technical support and usage guidance.

    For assistance, contact our customer service or technical support:

    touptek-astro.com/supports

    Important Notes

    • Color Variation: Filter coating colors may appear different under varying lighting conditions and viewing angles - this is normal optical behavior.
    • Product Improvements: We continually optimize our products, which may result in minor specification and appearance updates. Specifications are subject to change without notice. Please refer to the physical product for final details.

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