- Surfaces: precision polishing substrates with good parallelism and precise surfaces. - Polishing and coating: double-sided fine polishing achieves high parallelism. Coating: double-sided multi-layer coating; the back increases the penetration film and reduces reflex light. - High-contrast filter: the high-contrast filter (filter) is a harmful light filter that significantly reduces light pollution, suitable for city and suburban observation. - Size and purpose: this 1.25-inch filter is designed to enhance the image contrast of the subject. - Compatibility and performance: designed to fit 1.25-inch optics and improve subject contrast through precise surface finish and multi-layer coating. - Use scenarios: - Urban or suburban telescope observers can use this filter to reduce light pollution and improve the visibility of celestial objects. - Planets and the Moon can show enhanced edge contrast under light-polluted skies, aiding detail recognition. - In educational or outreach settings, this filter helps demonstrate how light-pollution reduction improves image clarity on compatible 1.25-inch instruments.