Astronomik L-3 UV-IR Block Filter - XL Clip-Filter for Canon EOS R and RP

Astronomik XL Clip Filter for mirrorless Full-frame Cameras Canon EOS R and RP

The luminance channel is probably the most important for a great final image! Now you can select a luminance filter perfectly matched to the kind of telescope you use, to get the highest signal and sharpest image for the luminance channel!

Astronomik now offers you a range of three different UV+IR blockers as luminance Filters. The different spectral window of each new luminance filters is designed to tune your setup to get the sharpest image from any optical design and any camera.

You want as much signal as possible so the filter should have the highest transmission possible with a wide spectral bandpass. This combination provides the greatest sensitivity and gives you the highest photon counts on your pixels.

While the high transmission level is a great aspect of the new Astronomik luminance filters, not all optical instruments or additional optical elements like correctors, field-flatteners or reducers have perfect colour correction, so it can be the width of the spectral band pass of the luminance filter that can cause problems. A band pass that is too wide will allow the transmission of incompletely focused light (chromatic aberration), making stars appear soft or bloated. In such cases, image processing can become difficult, so having a slightly narrowed spectral window in your luminance filter can reduce or eliminate this damaging effect.

Choosing the right filter characteristics

Depending on the color correction of your scope, you may use a wider spectral window for the luminance data. The L1 filter has the widest spectral window, the L2 is about the same as our current L-Filter and the L3 is much narrower.

If you use an optical system that is completely free of any chromatic aberration, you should get an L1 filter for your setup. For general use the L2 filter is well suited to most optical systems with a corrector, flattener or reducer in the optical train while the L3 filter is designed for users of refractors with a less-than-perfect color correction and in combination with the new Deep-Sky RGB filters, the L3 filter will minimise the problem of bluish halos around stars.

The transmission curve characteristics and coatings of 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 nebulas or galaxies.

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.

Additional note for observers working under light polluted skies:

If your observing site suffers from light pollution you should try to use Astronomik´s CLS-CCD as a replacement for the Luminance filter. The transmission curve of the CLS-CCD will give you approximately the same amount of energy in all three colour channels while blocking nearly all unwanted arifical light pollution. Customers who replaced the Lx filter with the CLS-CCD are amazed by the increased quality of their data. This small change gives you the opportunity to take much deeper images from your current observing site.

Compatibility

Canon cameras EOS R/R5/R5/RP/Ra (the latter can show strong reflections around bright stars)

Not compatible with Canon RF 35 mm f/1.8 IS MACRO lens.

Application

Mounting the Astronomik EOS R XL Clip Filter:

Mounting the Astronomik EOS R Clip Filter is very easy: You don´t need any tools and filters may be changed even at night without any problems.

Remove the lens and take the Clip Filter from its box. Insert the Clip-Filter into the body and push it in with two fingers, until it rests neatly. Re-install the lens and your camera is ready for imaging!

Removing the Astronomik EOS R XL Clip Filter:

A small hook is included for easy disassembly of the clip filter. Insert the hook into the slot in the clip filter and pull the clip filter forward out of the body.

Grab it with two fingers and put it back in the storage box. After attaching the lens, the camera can be used as usual.

The transmission curves:

On the horizontal axis, the wavelength is plotted in nanometers. 400 nm corresponds to a deep blue, at 520 nm the human eye sees green, at 600 nm red.

At 656 nm is the known H-alpha emission line of hydrogen, around 500 nm the two [O III] lines of oxygen, at 486 nm the H-beta line of hydrogen, around 672 nm the two [S II] lines of sulfur. The square brackets indicate that these are forbidden lines.

On the vertical axis the transmission is plotted in %.

The blue and cyan lines show the transmission of the filters.

A short guide for selecting the right filter

Lots of customers are overwhelmed by the vast number of filters offered by Astronomik. Due to that they give you a short guide how to select the right filter for your application below:

Astronomik´s normal recommendation for the "First Filter" is the CLS filter. The CLS blocks all unwanted artifical light pollution and natural airglow and gives you a dark background in your images. When using this filter you may expose much longer than without, so you will be able to pick much fainter structures and objects. The filter is designed in such a way that all objects are given in their natural colors - they would look the same if your human eye would be much more sensitive!

The CLS is the fist choice for any applications like night-scape photography and time lapse movies!

Important: The standard CLS has no built-in IR-blocker. In case your camera has been modified for astrophotography, please take the CLS-CCD which has a built-in IR-blocker!

If you have to work under a heavily light polluted sky, the UHC is a good choice too. Its transmission curve is very tight. It gives you the light from the Hß, [O III], Hα and [S II] lines in one single exposure. The reduction of light pollution is much stronger than the CLS/CLS-CCD, but the filter will work for gas nebulas only - any galaxies and open or globular clusters are filtered out! You will get "false colors" with the UHC, not natural colors like with the CLS/CLS-CCD.

The UHC-E has a more broadband light transmission. Here stars are less strongly suppressed, helpful for nebulae with star clusters.

If you want to die deeper into astrophotography, you should think about emission line filters centered on OIII, H-alpha and SII, available either with 12 nm or even 6 nm bandwidth. With these filters you can do ultra-deep images even under the worst sky you can imagine plus the full moon high up in the sky. The emission line filters isolate the light from a very tight range of wavelengths, don´t get any color information. If you want to create color images (false color like images from the HST), you will need all three filters to mix the three channels into a final color image.

When using DSLR cameras without IR cut filter in astronomy, we recommend the UV-IR block filters of the L-1, L-2 and L-3 series to correct chromatic aberrations when using refractive optics (camera lenses, refractors). Depending on the color correction of your scope you may use a wider spectral window for the Luminance data. The L1 filter has the widest spectral window, the L2 is about the same as our current L-Filter and the L3 is much narrower.

If you use an optical system that is more or less free of chromatic aberration you should get an L1 filter for your setup. For general use the L2 filter is well suited to most optical systems with a corrector, flattener or reducer in the optical train while the L3 filter is designed for users of refractors with a less-than-perfect color correction.

As protection against dust in DSLR cameras without IR cut filter, the MC clear glass filter is suitable. It blocks neither visible light nor UV or IR, but is parfocal with the other clip filters for Canon EOS R/RP full-frame cameras.

Especially made for planetary imaging are the ProPlanet IR pass filters. The IR light transmitted by them is less sensitive to air turbulence ("seeing"), which makes the images sharper, with increasingly longer wavelengths being increasingly less affected.