The Antlia 3nm Pro Ultra Narrowband 31mm filter set includes the following items:
The new Antlia 3nm Pro Ultra Narrowband filters boost the contrast of emission nebulae and supernova remnants for professional results, even under a bright sky affected by light pollution. The 3nm band pass is only 1% of the entire visible spectrum increasing the signal to noise ratio delivering high contrast images and extremely dark backgrounds. To even further enhance the contrast, and suppress the stray light and internal reflections, Antlia applies edge-blackening coating on each filter.
The maximum transmission is 85% - 90% and the transmission off band is only 0.001%. This is a value often undisclosed by other filter producers although it is critical to darken the sky background and minimise the halos around the stars. Blue-shift data shows that Antlia 3nm Pro filters can be used with nearly all systems as fast as f/3 with minimal loss in emission signal and meets the requirements of fast optics like Hyperstar and RASA.
Every filter is individually tested to ensure high the high quality standard that these filters have to meet end specifically the uniform thickness of the filter that deviate n more than ±0.05 from specifications.
Each filter cuts off the ultraviolet and infrared light so there is no need to use the IR-cut filter.
DO NOT LOOK AT THE SUN WITH THE ANTLIA FILTERS. Serious eye damage will occur.
|Passing band||3 nm (FWHM)|
|Glass thickness||2.0 mm ±0.05|
|Optical flatness||1/4 λ (wavefront)|
|Bandpass transmission||85% - 90%|
|Off-band transmission||<0.001% (OD5) @ 300-1000 nm|
|Coating||Double-sided multilayer nano-coating|
|Surface quality||60/40 (in accordance with US military watch MIL-O-13830)|
|Glass type||Schott monolithic optical substrate (non glued)|
|Filter options||Mounted 1.25", 2", Unmounted 31mm, 36mm|