Filter Optolong L-Pro anti-light pollution broadband 2"

Filter Optolong L-Pro anti-light pollution broadband 2"

Product description

The L-pro filter has five transmission bands (the most of any anti-pollution filter on the market), covering more of the visible spectrum to provide more realistic colors. The transmission windows coincide with the OIII, Hbeta, NII, Halfa and SII wavelengths (and other windows where there are no spectral emissions from sodium vapor or mercury vapor bulbs), so the L-pro can be considered a multi-window nebular filter. Its filter factor is 1.5 (1.5 times more exposure time than without filter). As a filter that is not overly restrictive, it is the optimal filter for areas with medium light pollution.

The filter is made of optical glass with a flatness level of λ / 4 on both surfaces (the surface irregularities are

The L-Pro has an ultra-clean substrate after passing through 13 ultrasonic cleaning tanks and purified water, to effectively remove any remaining impurities and dust.

Its outermost coating with ion-assisted electron beam evaporation deposition technology provides enhanced durability and scratch resistance, as well as CWL (center wavelength) stability unaffected by temperature changes.

All L-Pro filters undergo extensive quality control: each filter is individually tested with spectrophotometer and laser interferometer to ensure that its output spectrum and wavelength front is adequate.

Technical specifications:

• Peak transmission: T > 90%
• Spectral range: 380-750 nm
• Optical density: 90% blockage of light pollution
• Filter factor: 1.5 (requires 1.5 times more exposure than without filter)
• Spectral windows of astronomical interest: OIII, Hbeta, NII, Halfa and SII
• Surface quality: 60/40
• RMS of transmitted wavefront: λ / 4
• Parallelism (arcsec): 30"
• Format: Threaded to the eyepiece barrel
• Size: 2"

Filter Optolong L-Pro broadband anti-light pollution filter 2"