Astronomik Blue Filter Type 2c, Clip-Filter for Canon EOS Full Frame cameras 5D and 6D

A filter especially designed for astrophotography with CCD cameras. These filters provide a natural color reproduction of planets, stars, emission and reflection nebulas.

The transmission properties of the L-RGB Typ 2c filters are optimized for CCD astrophotography. The set allows to take images in correct colour for all types of objects. Where other brands make strange compromises, Astronomik does the best colour reproduction possible. Both, stars as well as objects that emit only in spectral lines, are reproduced in their true colors. You get CCD images with perfect colors, as if the objects where bright enough to be seen with photopic vision. This feature is the main difference between Astronomik LRGB filters an those of other manufacturers.

The following aspects have been most important for the design of Astronomik LRGB filters:

simple image processing for the user

highest transmission (nearly 100%) for short exposure times

adjusted transmissions of the individual filters for optimal color reproduction in the sRGB color space

integrated IR blocking up to approx. 1150 nm

can be combined to form a complete LRGB set

the use of industry standards

Astronomik doesn´t stop thinking at the step of taking the picture. More important a tool should be given to the astrophotographers that offers a simple and elegant editing process. To maintain the colour, they calculated their filterset for the sRGB color space, that is used as an industry standard from most manufacturers of monitors, printers and imaging software. As a user you do not need to spend time to learn about colourimetry and colour spaces. Astronomik have solved the special problems of astrophotography for you.

Due to the high-precision machining of the carrier substrate, Astronomik filters are parfocal with wedge errors below all usual margins. In order not to be the bottleneck in a high-quality optical system, Astronomik filters are of course diffraction limited. Issues concerning focal distances as well as the exact location of the images of each colour image are not a problem at all!

Main use:

The L-RGB filter set divides the spectrum into its components red, green, blue and luminance. Thus colour separation can be achieved with pure b/w CCD sensors. The separation corresponds to the colour sensitivity of the human eye according to DIN 5032. By using the sRGB color space, it is possible to maintain the color of the image throughout the entire image processing and output. With an Astronomik L-RGB filter set and your camera, you create ideal raw material for imageprocessing in the sRGB color space.

Other uses:

In combination with the Astronomik line filters, your images will show interesting details of astronomical objects. For example, the red image can be enhanced by H-alpha or the green image by [O III].

For planetary observation and photography, the color filters are gladly "misused".

Technical Data:

Parfocal with other Astronomik filters

Glass thickness: 1 mm

Completely resistant against high humidity, scratches and aging effects

Diffraction limited, the filter will not reduce the optical performance of your telescope!

Astronomik filters are delivered in a high-quality, long lasting, filter box

Filter transmission curve:

The horizontal axis is the wavelength in nanometers (nm). 400 nm is deep blue, at 520 nm the human eye senses green and at 600 nm red. At 656 nm is the famous "H-Alpha" emission line of hydrogen.

The transmission in % is plotted on the vertical axis.

The blue line shows the transmission of the filter.

Visual filters: The grey line in the background shows the relative sensitivity of the human eye at night. The maximum is at ~510 nm and drops to longer and shorter wavelengths. You can easily see, that you can´t see anything of the H-alpha line at night (even if you can during daylight!) The sensitivity at 656 nm is 0% at night!

Photographic filters: The grey line in the background shows the sensitivity of a typical CCD sensor.

The most important artifical emission lines are shown in orange. The artifical light pollution is dominated by see mercury (Hg) and sodium (Na), which are used in nearly all streetlights.

The most important emission lines from nebulas are shown in green. The most important lines are from ionized hydrogen (H-alpha and H-beta) and double ionized oyxgen ([O III]). The square brackets indicate that these lines are forbidden.

The Challenge:

Do you own a Canon EOS digital camera for astro-imaging? Then you have surely encountered the following problems:

Large filters for large camera lens objectives are very expensive.

If you place a filter holder between your camera body and lens, you loose the ability to focus to infinity.

For very fast (low f/ number) telescopes like the Vixen R200SS or the Takahashi “Epsilon” astrograph, a filter drawer or a filter wheel cannot be used since the distance to the corrector lenses would be changed.

With long exposure times, your camera’s sensor chip is exposed to more dust.

With the Astronomik Clip-Filter System you can take care of all of these problems at once!

The patented Astronomik Clip-Filters are made of black anodized aluminum and laser-cut on state-of-the-art machines. They can be inserted within seconds directly into the camera body. There are no changes necessary and all lens functions (focus, screen, image stabilization) remain operational!

Almost all Canon system lenses (with the exception of the EF-S series) and all M42 and T2 lens adapters, can be used with the Astronomik Clip-Filter System. The Clip-Filter System also acts as an outstanding dust shield, which prevents the possibility of dust settling on the sensor during long time exposure (The MC-Clear filter does not have a filter effect and only acts as a dust shield.)

Compatibility:

Canon EOS 5D and 6D with full-size sensor are compatible.

5D Mk I will work without LiveView only, the 6D MkII will not work with XL Clip-filters.

Please note that the XL-Clip filters will not work with the Canon 5DS, 5DSR, and the 5D Mk IV.

The filters are also not suitable for Canon EOS, EOS RP and EOS RP Astro!