The Antlia SHO 2.5nm Ultra series filters are extra narrowband filters made with quartz glass which undergoes precisely controlled coating processes to ensure optimal performance. This 2-inch mounted set includes H-a, SII and OIII filters and is designed with a FWHM (full width half maximum) of 2.5nm +0.3/-0.1nm and a transmission efficiency >93-95% at the central wavelength.
The quartz glass possesses an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When combined with advanced coating processes, these filters exhibit remarkable durability for imaging and research in the most challenging environmental conditions.
Compared to the Antlia 3nm Pro series, the Antlia SHO 2.5nm Ultra series filters exhibit higher transmittance with Ha/SII≥95% and OIII≥93%. The filters are estimated to improve signal by 20-30% in images. Additionally, the Ultra series offers a narrower FWHM of 2.5nm+0.3/-0.1nm, resulting in a high signal to noise ratio for deep sky imaging.
The Antlia SHO 2.5nm Ultra series filters features include:
– High transmittance (Ha/SII≥95%, OIII≥93% and the narrow FWHM 2.5nm +0.3/-0.1nm to maximize contrast.
– Flat-top spectrum minimizes the loss in transmission due to the center wavelength (CWL)-shift.
– Out of band blocking specification is designed to OD5 (0.001%) to block interference from other wavelengths and minimize halos around bright stars.
– Made of quartz glass, excellent durability and thermal stability, better fracture resistance and scratch resistance, improved coating resilience to cleaning.
– Filters are resistant to scratches
– Identical filter thickness to existing standards and double-sided fine polishing, with care for parfocality.
– The SHO 2.5nm Ultra filters are recommended for use in optics with a focus ratio of ≥ f/3.5 for best optical performance.
– 100% of production are scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra and transmission.
– All Antlia filters are coated to the edge of the substrate and unmounted narrowband filters are edge blackened to eliminate internal reflections from stray light.
You can learn more about the Antlia SHO 2.5nm Ultra series filters here.
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