Optolong L-Pro 2'' Filter

This filter allows astrophotography even near the city and offers the best possible results. Optolong L-Pro fog filters provide a significant contrast boost and allow approximately three times longer exposure times with DSLR cameras, color astronomical cameras, and MONO cameras.

The filter offers better color balance than comparable filters for DSLRs and modern color one-shot cameras with CMOS sensors, such as those offered by ZWO. Of course, the filter also provides significant improvements with mono cameras, for example, in luminance capture.

Optolong filter

This filter is designed to enhance the contrast of deep-sky objects and attenuate the celestial background. This is achieved through complex transmission properties, allowing the lines of deep-sky objects (H-Alpha, O-III, N-II, H-Beta, S-II, etc.) to pass through and stray light emissions (e.g., the Hg line or emission from sodium vapor lamps) to be suppressed. Furthermore, the celestial background, with its undesirable oxygen emissions from the atmosphere (known as "skyglow"), is also attenuated. This filter is especially suitable for light-polluted areas and is suitable for both visual observation (depending on the mount) and astrophotography.

Unlike other filters that reduce light pollution, such as UHC or CLS filters, this is a multi-band pass filter that barely affects color rendering. This makes it also suitable for photographing continuous objects, such as emission nebulae, galaxies, globular clusters, reflection nebulae, etc. This allows them to shine up to three times brighter than without a filter.

Coating properties:

The treatments are not mixed into the optical substrate, but are applied to the surface by electron beam evaporation followed by ion beam-assisted deposition (IBAD). This special process provides extreme durability and scratch resistance, as well as a high central wavelength constant (CWL) and prevents thermal drift. Furthermore, transmission in the pass region and optical density in the blocking region are high.

Please note that this filter CANNOT be used as a sunscreen on its own!