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Astronomik L-2 UV-IR Blocking Filter - 50 mm Round - L2-50R

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SKU: ASF-L2-50R

Astronomik UV-IR Blocking Luminance Filters


For spectacular results, the Luminance channel is probably the most vital factor for image creation. To gain the greatest amount of signal possible, the filter being employed needs to have a wide spectral bandpass to realize the highest transmission possible. These two aspects combine to enable peak sensitivity and provide maximum photon counts on your pixels. Not all optical instruments, or supplemental optical elements like correctors, flatteners, or reducers have ideal color correction. So although the high transmission level of these new Astronomik Luminance filters is a terrific feature, the larger spectral band pass width of this filter can produce problems such as soft or bloated stars resulting from excess transmission of light that is not completely focused (chromatic aberration). Image processing can be challenging when this occurs. However, this detrimental effect can be reduced or even completely eradicated by having a Luminance filter with a spectral window that is slightly more narrow.

Astronomik has now expanded their Luminance filter line so that you can have all the tools required to gather the best obtainable data. There is a filter suitable for any telescope type that you may select to achieve the highest signal and sharpest image for the Luminance channel.

The color correction of your telescope will determine whether you should use a filter with a wider spectral window for the Luminance data. For the widest spectral window, choose the L1 filter; and for the narrowest spectral window, choose the L3 filter. The middle ground contains the L2 which has about the same size spectral window as Astronomik's current L-Filter.

For optical systems that are totally free of chromatic aberration, the L1 filter is the best option. When working with most optical systems using a corrector, flattener, or reducer in the optical train for common use, the L2 is your choice. Lastly, for users with refractors that feature less than perfect color correction, the L3 filter works best. Also, the L3 can combine with Astronomik's new Deep-Sky RGB filters to lessen the bluish halo effect around stars.

The transmission curve characteristics and coatings on the new Luminance filters have been designed and engineered in such a way that no halos or reflections will be visible. Even with bright stars in the field of view you will be able to reveal the faintest structures in galaxies or nebulae.

Like all Astronomik Filters, the new Luminance filters are made using an extremely durable and scratch resistant coating, deposited on the finest polished optical substrate, which is free of any striae or internal strains. All substrates are made to exactly the same thickness, so all Astronomik filters are parfocal.

Astronomik UV-IR Blocking Luminance Filter Highlights


  • Parfocal with all filters carried by Astronomik
  • Offers total protection from the effects of scratching, aging, and high humidity
  • Diffraction limited, this filter will not compromise the optical performance of your telescope
  • Astronomik filters arrive with a long-lasting plastic filter case of supreme quality