Dual-narrow band astronomical filters from Shape Optics Technologies Pte Ltd are engineered to enhance astrophotography by isolating specific emission lines while suppressing unwanted background light. By narrowing the spectral bands that reach the sensor, these filters significantly increase nebula contrast and reduce sky glow, making them ideal for imaging under light-polluted conditions.
Designed for visual observation and CCD/CMOS imaging, SOT’s dual-band filters deliver high in-band transmission with steep spectral edges, enabling cleaner captures of faint celestial structures. Standard designs are available, and custom solutions can be produced to match specific emission lines or telescope/camera combinations.
Key Features
- Dual-Narrow Band Design – Transmits two targeted emission bands for enhanced nebula contrast
- Light-Pollution Suppression – Effectively blocks common urban light pollution
- High Transmittance – T ≥ 90% in the passbands for strong signal capture
- Improved SNR – Darkens sky background to boost nebula signal-to-noise ratio
- Customizable Performance – Wavelengths, bandwidths, and OD tailored to your setup
Spectrum Transmission
Standard transmission curves provide two well-defined, high-throughput passbands with strong out-of-band blocking. If standard wavelengths do not meet your needs, custom spectral designs are available upon request.
Coating Quality & Environmental Reliability
All filters are qualified to stringent standards to ensure long-term stability:
- Adhesion (MIL-C-675C) – No blistering or peeling after repeated tape removal
- Thermal Cycling – −62 °C to +71 °C with no coating detachment
- Abrasion Resistance (MIL-C-675C / CCC-C-440) – No surface damage after 25 cycles at 1.0 lb load
- Humidity Resistance – 95–100% RH at 49 °C for 24 h without defects
- Solvent Resistance – Stable after acetone and alcohol exposure
- Salt Spray – 100 h at 35 °C, 5% salt concentration with no degradation
Standard Specifications
| Model | CWL (nm) | Transmittance | FWHM (nm) | Optical Density | Notes |
|---|---|---|---|---|---|
| Dual-Narrow Band Filter 1 | 350 ± 3 | ≥ 90% | 20 ± 5 | OD ≥ 3 @ 350–1100 | Customizable for higher OD |
| Dual-Narrow Band Filter 2 | 500 ± 3 | ≥ 90% | 20 ± 5 | OD ≥ 3 @ 350–1100 | Customizable for higher OD |
Additional wavelength pairs and bandwidths available upon request.
Typical Applications
- Astronomical Telescope Imaging – Enhanced nebula contrast in light-polluted skies
- Astrophotography – Cleaner, higher-detail images of nebulae and galaxies
- Urban Astronomy – Reduced impact of artificial lighting
- Professional Observatories – Improved data quality for scientific imaging
Need a custom dual-band astro filter?
Contact us with your desired emission lines, bandwidths, OD targets, and system details for a tailored solution.