Antlia H-Alpha 2.5nm Ultra Filter - 2"
Antlia 2.5nm H-Alpha Ultra Filter - Extra Narrowband - 2" Mounted
The Antlia Hydrogen-Alpha 2.5nm Ultra Filter, which is part of the Antlia SHO series of extra narrowband filters, is made with quartz glass and has undergone precisely controlled coating processes to ensure optimal performance. The 2.5nm Ultra OIII Filter is designed with a FWHM (full width half maximum) of 2.5 nm +0.3/-0.1nm and a transmission efficiency >95% at the Central Wavelength.
The quartz glass offers an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When combined with advanced coating processes, this filter exhibits remarkable durability for imaging and research in the most challenging environmental conditions.
Compared to the Antlia 3nm Pro series, the 2.5nm H-Alpha Ultra Filter, coated on quartz glass, exhibits higher transmittance with >95% at CWL, or Central Wavelength. This filter is estimated to improve signal by 20-30% in your images. Additionally, the Ultra series narrowband Ha filter boasts a narrower FWHM of 2.5 nm+0.3/-0.1nm, resulting in an exceptionally high Signal to Noise Ratio for deep sky photography.
Antlia 2.5nm H-Alpha Ultra Filter Specifications
- FWHM: 2.5 nm +0.3/0.1 nm
- CWL: 656.3 nm
- Peak Transmission: 95%
- Blocking: OD5 (0.001%)
- Filter Thickness: 2 mm +/- 0.05 mm
- Size: 2" Mounted
Antlia 2.5nm H-Alpha Ultra Filter Features
- High transmittance of 95% and narrow FWHM 2.5 nm +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, improved coating resilience to cleaning
- Filters are resistant to scratches
- Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality
- The SHO 2.5nm Ultra filters are recommended for use in optics with a Focal 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