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Astronomik L-1 UV-IR Blocking Filter - 27 mm Round - L1-27

SKU: ASF-L1-27

Astronomik UV-IR Blocking Luminance Filters

The Luminance channel is perhaps the most critical aspect of creating a superb final image. In order to achieve the greatest signal quantity, the filter being used should have the highest possible transmission with a wide spectral bandpass. These two elements allow for the highest sensitivity and give you maximum photon counts on your pixels. Even though the high level of transmission is an excellent characteristic of these new Luminance filters, perfect color correction is not universal on all optical instruments, or additional optical elements such as correctors, reducers, and flatteners. Thus, problems may arise due to the Luminance filter's spectral bandpass width. Stars may appear soft or bloated due to the transmission of incompletely focused light (chromatic aberration) if the band pass is too wide. When this happens, image processing can be difficult. However, this damaging result can be reduced or completely nullified by having a spectral window that is slightly narrower in your Luminance filter.

In order to provide users with all the necessary tools to gather the best possible data, Astronomik has bolstered their Luminance filter line. Now you can choose Luminance filter ideally suited for your telescope type to achieve the highest signal and sharpest image for the Luminance channel.

The spectral window width you choose for Luminace data will be determined by the color correction of your telescope. The widest spectral window is offered by the L1, while the L3 provides the most narrow. In the middle is the L2 which is about the same as the current Astronomik 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 correcto, 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 other filters carried by Astronomik
  • Offers complete resistance to the impacts of scratching, aging, and high humidity
  • Diffraction limited for no compromise in your telescope system's optical performance
  • Astronomik filters come with a long-lasting, supreme quality plastic filter box