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Astronomik L-2 UV-IR Blocking Filter - SCT Rear Cell - L2-SCT

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SKU: ASF-L2-SCT

Astronomik UV-IR Blocking Luminance Filters


In order to achieve spectacular final image results, the Luminance channel is probably the most critical element. Therefore the filter being used should feature the highest possible transmission with a wide spectral bandpass in order to gain as much signal as you can. These two factors enable the greatest sensitivity and provide you with the highest photon counts on your pixels. Although the high level of transmission these new Astronomik Luminance filters have is a terrific feature, not all optical instruments (or additional optical elements such as correctors, reducers, and flatteners) can boast ideal color correction. Because of this, a wider spectral band pass can cause problems like the appearance of soft or bloated stars that are the result of insufficiently focused light (chromatic aberration). In such instances, image processing can be a challenge. So having a spectral window that is marginally more narrow can either totally eliminate or at least lessen this damaging effect.

Astronomik has recently expanded their Luminance filter line to provide you with all the tools needed to gather the best possible data. Now you can select the Luminance filter best equipped for your specific telescope system to get the highest signal with the most clear image for 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.

If your optical system is completely chromatic aberration free, you should get an L1 filter for your setup. For general use with most optical systems employing a corrector, flattener or reducer in the optical train, the L2 is optimal. The L3 filter is made for users with refractors that have less than ideal color correction. Plus, when used in conjunction with Astronomik's new Deep-Sky RGB filters, the L3 filter will reduce that annoying bluish halo 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. The mechanical thickness of the cell is 14.7mm, the glass installed is 1mm thick. As result the filter adds 14.4mm to the backfocus.

Astronomik UV-IR Blocking Luminance Filter Highlights


  • Parfocal with any other filter made by Astronomik
  • Fully protects against the effects of scratching, aging, and high humidity
  • This filter is diffraction limited and thus will not lower the optical performance level of your telescope
  • The mechanical thickness of the cell is 14.7mm, the glass installed is 1mm thick
  • Adds 14.4mm to the backfocus
  • Astronomik filters are delivered with a long-lasting, high quality plastic storage container