ToupTek Astro SHO Narrowband Filter Set
Precisely captures specific wavelength emission lines, enhances target signal-to-noise ratio, revealing stunning emission nebula details
Narrowband filters are essential accessories in astrophotography, used to isolate specific wavelength emission lines and enhance target signal-to-noise ratio—particularly suitable for capturing spectacular emission nebulae.
ToupTek Astro SHO narrowband filters are precisely tuned to the three primary ionized emission lines of star-forming regions:
- Hα (656.3nm)
- SII (671.6nm)
- OIII (500.7nm)
By using these filters, you can effectively block urban light pollution and background stray light, significantly enhancing signal contrast and revealing incredible detail—enabling you to achieve Hubble-like palettes (SHO composites) in your astrophotography.
Technical Parameters
Size Specifications
36mm (unmounted) / 1.25" / 2"
Glass Thickness
2mm
Transmission
>90%
Glass Material
Quartz Glass
Frame Material
Aluminum Alloy
OD Value
≥5.0
Transmission Ranges
SII
Center Wavelength 671.6nm
Hα
Center Wavelength 656.3nm
OIII
Center Wavelength 500.7nm
Full Width at Half Maximum (FWHM)
36mm:
Hα (4nm) / SII (4nm) / OIII (4nm)
1.25" & 2":
Hα (6.5nm) / SII (6.5nm) / OIII (6.5nm)
Surface Treatment: Dual-side high-precision optical polishing
Coating Technology: IAD (Ion Assisted Deposition)
Coating System Design: AR anti-reflection coating + quartz glass + precision cut-off coating layer
Core Features
Precise narrowband design effectively suppresses background noise while highlighting emission structures of different elements, making celestial layers clearer and detail levels richer.
SII Filter: Center wavelength 671.6nm, FWHM 4nm.
Enhances weak signal detection, revealing structural layers through ionized sulfur distribution. When combined with Hα, significantly improves image contrast.
Enhances weak signal detection, revealing structural layers through ionized sulfur distribution. When combined with Hα, significantly improves image contrast.
Hα Filter: Center wavelength 656.3nm, FWHM 4nm.
Optimized for hydrogen ionization regions, primary channel for capturing nebula morphology.
Optimized for hydrogen ionization regions, primary channel for capturing nebula morphology.
OIII Filter: Center wavelength 500.7nm (OIII emission line), FWHM 4nm.
Used to reveal high-energy excitation regions, particularly effective for presenting blue-green nebula details.
Used to reveal high-energy excitation regions, particularly effective for presenting blue-green nebula details.
*1.25-inch and 2-inch filters have FWHM of 6.5nm.
ToupTek Astro's complete filter series utilizes high-quality colorless transparent quartz glass with >90% high transmission, high purity, excellent blue-violet band transmission, and superior thermal stability—ideal for various demanding astronomical imaging applications.
Employs IAD (Ion Assisted Deposition) coating technology. While more expensive than traditional vacuum evaporation, it produces denser, more uniform coatings with superior durability, corrosion resistance, and environmental stability.
ToupTek Astro filters employ proprietary multi-layer systems: single-side cut-off coating, front surface AR anti-reflection coating, and edge blackening treatment. This combination effectively reduces internal reflections and stray light while ensuring coating integrity and extended service life.
All channel filters achieve cut-off depth of OD≥5.0, effectively blocking non-target spectral regions, preventing band crosstalk and color shifts, achieving accurate and natural color reproduction.
Filter edges feature black matte treatment, minimizing stray light, ensuring transmission rates, reducing glare, and enhancing image contrast.
- 36mm filters: Feature recessed black ring facing telescope for quick orientation identification
- 1.25" and 2" filters: Equipped with threaded aluminum frames for direct screw-in installation, ensuring quick tool-free installation
All filters feature monolithic, adhesive-free construction.
36mm: Recommended for APS-C and smaller sensor formats
1.25": Recommended for 1-inch and smaller sensor cameras
2": Recommended for full-frame and smaller sensor cameras
Compatible with various brands of 7-position 36mm, 8-position 1.25-inch, and 5-position 2-inch motorized filter wheels, providing broader compatibility options.
Spectral Response Curves
Spectral Chart Reading Guide
- Horizontal axis represents wavelength (unit: nm), vertical axis represents transmission (percentage %)
-
Blue line: SII (672.4nm) Red line: Hα (656nm) Green line: OIII (500.7nm)
- Emission nebula signal bands are primarily located at 656nm (Hα), 500.7nm (OIII), and similar wavelengths
- Light pollution peaks typically occur near 540nm and 590nm (sodium/mercury lamp bands)
Our astronomical filter transmission regions are carefully designed to avoid these interference bands, ensuring maximum signal clarity, enhanced contrast, and high image purity for deep sky imaging.
ToupTek Astro SHO Narrowband Filter Imaging Results
IC5070
Photographer: voice
Telescope: Sky-Watcher
Mount: UMI
Camera: ToupTek Astro ATR2600M
Filters: ToupTek Astro 36mm LRGB&SHO
Exposure: Hα: 30×600s ; SII: 30×600s ; OIII: 30×600s
Total exposure time: 15 hours
IC443
Photographer: voice
Telescope: Sky-Watcher F3.4
Camera: ToupTek Astro ATR2600M / ATR2600C
Mount: UMI
Filters: ToupTek Astro 36mm HSO
Processing: Narrowband composite using HSO channel mapping
Total exposure time: 20 hours
NGC2237
Photographer: 原上行川
Telescope: Askar SQA55
Camera: ToupTek Astro ATR2600M
Mount: iOptron HAE16C
Filters: ToupTek Astro 36mm HSO
Wireless Controller: StellaVita
Exposure: Hα: 71 ; OIII: 63 ; SII: 49
Total exposure time: 15 hours
M16
Photographer: Yahushua
Telescope: Askar 130HNT28-AL
Camera: ToupTek Astro ATR585M
Mount: iOptron CEM26
Guide Camera: G3M2210M
Filters: ToupTek Astro 1.25" HSO
Total exposure time: 7 hours
NGC6357
Photographer: voice
Telescope: Sky-Watcher
Camera: ASI2600M
Filters: ToupTek Astro 2" HSO
Mount: UMi 17
Exposure: Hα: 36×600s ; SII: 36×600s ; OIII: 36×600s
Total exposure time: 18 hours
Installation Guide
36mm Unmounted Filters
Special coating eliminates ghosting. During installation, orient the side with the recessed black ring toward the telescope for instant positioning and improved convenience.
1.25" and 2" Filters
Special coating eliminates concerns about front/back installation—simply screw in for quick, tool-free installation.
Warranty & Service
Quality Assurance Testing
Every filter undergoes spectral testing and rigorous screening before shipment to ensure optical performance consistency.
Warranty Policy
Includes two-year warranty covering manufacturing defects, plus professional technical support and usage guidance.
Technical Support
For assistance, please contact our support team:
ToupTek Astro Technical Support
Important Notes
Color Variations:
Filter coating colors may appear different under various lighting conditions and viewing angles—this is a normal optical phenomenon.
Product Improvements:
We continuously optimize our products, which may result in minor updates to specifications and appearance. Specifications subject to change without notice. Please refer to actual products.