Antlia H-Alpha Filter - 2.8nm Extra Narrowband Filters - 36mm Unmounted

Antlia H-a, SII and OIII 2.8nm Ultra Filter - Extra Narrowband filters   36mm unmounted

The Antlia SHO 2.8nm Ultra series filters use   quartz glass and are manufactured under precisely controlled coating processes. The Ultra series are optimized with a FWHM (full width half maximum) of 2.8nm +0.5/-0.1nm and a transmission efficiency >95-97% at the emission wavelength. The result is a very high Signal to Noise Ratio.

 The quartz glass has an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When these superior glass characteristics are combined with advanced coating processes, these filters will provide excellent durability for imaging and research in the toughest environmental conditions.

Compared with 3nm Pro series, 2.8nm Ultra series coated on quartz glass and showed higher transmittance Ha/SII＞97%，OIII＞95%. It is estimated that these filters will provide 20-30% signal improvement in your images as compared to the 3nm Pro series. In addition, the Ultra series has a 10% narrower FWHM 2.8nm+0.5/-0.1nm. The Ultra series narrowband filters will allow you to capture improved contrast and structural detail.

Technical Specifications:

 Sizes and MAP Prices：

The main features and application:

- High transmittance （Ha/SII＞97%，OIII＞95%）and the narrow FWHM 2.8nm +0.5/-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;

- Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality

- SHO 2.8nm Ultra filters can be used down to f/3.5 systems with minimal loss of signal. (This does not mean that optics with faster focal ratios will not be applicable, the flat-top design reduce the effect of wavelength shift and you can still use the 2.8nm Ultra narrowband);

- 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；

- Warranty: 3-years against delamination.

Spectrum Curves and product images:

 All the 2.8nm Ultra filters are 100% scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra.

Filter Ring:

Antlia standard ring:1.25’’ (M28.5*0.6)，2’’(M48*0.75)

Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture

Black Anodized Finish

Laser Engraving No Fading

Not Recommended:

Solar imaging

Night visual observation

Not Permitted:

DO NOT LOOK AT THE SUN WITH THIS FILTER

Serious eye damage will result if you fail to observe the warning.