Antlia 3nm Narrowband H-alpha (Ha) Pro Filter - 50mm x 50mm Square Unmounted

Antlia H-alpha 3nm Pro filters are designed to provide 88% transmission in the 656.3nm line, giving you maximum signal and well-defined nebula structures.

Conventional wider narrowband filters cause high transmission loss due to the strong center wavelength shift (CWL). We guarantee a T>88% within the 1nm range of the central bandwidth, which means that the 3nm Pro narrow band filter can guarantee high transmittance to work with both long focal ratios and fast optical systems. The blueshift data shows that Antlia 3nm Pro filters can be used with almost all systems as fast as f/3 with minimal loss of the emission signal and meet the requirements of fast optics such as Hyperstar and RASA.

The out-of-band blocking specification is OD5 (0.001%), providing excellent SNR (signal-to-noise ratio) and an effective cut-off rate to minimize interference from other wavelengths. Pro 3 nm astrophotography filters with enhanced sharp cut-off are designed to minimize halos around bright stars.

Application and performance

High transmittance and minimum bandwidth to maximize contrast

Steep spectral profile minimizes halos around bright stars

Single substrate to eliminate internal reflections

Narrow band objects: H-alpha emission nebulae, planetary nebulae, Wolf Rayet nebulae and supernova remnants

Use in light-contaminated areas and dark locations

Extends imaging time when moon is present

Antlia Pro Narrowband filters can be used in up to F/3 systems with slight signal loss

All Antlia Narrowband filters have blackened edges to eliminate internal stray light reflections

Superior optical reliability reduces image post processing

This filter is not suitable for deep sky objects that do not contain H-alpha emissions.

Technical Specifications

Basic substrate: Schott optical substrate

Filter thickness: 3 mm+/-0.05 mm

FWHM (Full width at half maximum): 3nm

CWL (Center Wavelength): 656.3nmnm

Maximum transmission: ＞88%.

Blocking: > 5 OD(0.001% out-of-band blocking) @ 300-1000nm

Surface Quality: S/D (scratch/degradation)= 60/40 (refer to MIL-O-13830)

Transmitted wavefront: Lambda/4 or better.

Parallelism: less than 30 arcsec

Single substrate / unbonded

Warranty: 3 years against delamination

Not recommended

Solar observation and imaging

Visual observation

DO NOT LOOK AT THE SUN WITH FILTERS ANTLIA.

Failure to heed this warning can result in serious eye injury.

When designing filters for astronomical imaging systems, we look at how they will work together with the optical systems, carefully designing the blocking and bandpass parameters for optimum performance. The out-of-band blocking index is a very important performance index, as it is designed to sharply attenuate out-of-band wavelengths. The result is that the Antlia H-alpha 3nm Pro filter offers excellent contrast with extremely dark backgrounds, while providing high transmission of the H-alpha signal. These types of filters are more difficult to produce at a consistently high level of quality.

Each filter is individually tested and scanned to ensure that the quality meets high performance parameters. The end result is a filter that achieves excellent contrast, but at a higher production cost. We believe the price-performance ratio is more favorable than similar premium filters on the market.