Astronomik L-2 UV IR Block Filter - Clip Filter for Pentax K1 and K1 Mk II Cameras

Astronomik Luminance L-1, L-2, L-3 Filter

The luminance channel is probably most important for a successful astrophoto! Sharpness, contrast and low noise of the luminance data are crucial to achieve the best possible quality in the final result! The Astronomik L-2 filter is the most versatile of these filters.

The task of the L-filter is to have the maximum transmission over the complete visible spectrum, because the combination of the widest possible passband and high transmission makes it possible to capture the largest possible number of photons.

In the "real" world, unfortunately, not all telescopes or add-ons like correctors, field flatteners or Shapley lenses have perfect color correction. An L-filter that is too broadband will pass wavelengths for which your optics are not properly corrected. The result is unsightly bloated, out-of-focus stars that do not match the RGB color channels.

The new Astronomik L-1, L-2 and L-3 filters eliminate or reduce the problem.

Selection of the correct filter characteristic

Depending on the color correction of the instruments used, the L filter with the largest passband should be used. The L-1 filter has by far the largest spectral passband, whereas the L-3 filter has the narrowest spectral window. The L-2 filter corresponds to a "normal" L filter. It is the most versatile filter.

If your used optics can be classified as commonly " chromatic aberration free", the L-1 filter is the right choice. For general use, e.g. on telescopes of different color purity or the use of additional refractive elements in the beam path, we recommend the Astronomik L-2 version. For "colorful" optics, we recommend the Astronomik L-3 filter to increase image sharpness.

Like all Astronomik filters, the L-1, L-2 and L-3 filters have an extremely resistant and durable coating, applied to a special fine-optical substrate, which is also used in space travel. The basic requirement for such material is freedom from streaks, stresses and bubbles.

A complement for photographers under light-polluted skies:

Use the Astronomik CLS CCD filter instead of a luminance filter! You get an L-signal without the lines of sodium and mercury vapor lamps, with much less background noise. Highly satisfied feedback from customers all over the world confirms the advantages of the CLS-CCD filter for the luminance channel and makes color photography of the deep sky possible in some regions in the first place!