Optolong L-Pro Filter for deep space objects

1. L-Pro Introduction 

Optolong L-Pro (L-Professional) filter is designed to improve the visibility of various deepsky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere.

Main Use and Performance

Suitable for visual observation and astrophotography.

L-Pro filter has a very low transmission reduction rate against continuous spectrum space objects, and thus is quite effective in suppressing light pollution sources when shooting galaxies, reflection nebulae and globular star clusters. The same holds true for visual star observations.

WARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.

Technical Data

• Optical glass fine material
• Spectrum: 380-750nm
• Surface Quality: 60/40 (Refer to MIL-O-13830)
• Fine-optically polished to ensure accurate 1/4 wavefront and < 30 seconds parallelism over the both surfaces
• High transmission at major nebula emission lines (i.e. H-alpha 656nm, OIII 496nm&500nm, SII 672nm and H-beta 486nm).
• Precision off-band blocking, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).

2. L-Pro Spectrum and Characteristic