Astronomik 6 nm H Alpha CCD Clip Filter for Canon EOS full-frame size sensor cameras

The Astronomik 6 nm H-alpha CCD Clip-Filter for Canon EOS full frame size cameras is a narrow band-pass filter for hydrogen nebulae and can be inserted into the camera body within seconds.

Different from the 12 nm filter, contrast is enhanced strongly, helpful in heavily light polluted areas.

All transmission curves of the 6 nm filter are measured individually. Because of this procedure you can get the optimum filter for your telescope: If you place a direct order, please specify the focal ratio of your instrument, and we will select the best filter for your setup.

Note: the optical viewfinder does not work with installed EOS XL Clip-Filter, as the flip-mirror is fixed in the upper position!

Alternatives:

If you plan to do (false-)color imaging with other emission line filters, you should get the filter with 12 nm FWHM. Images taken with filters with differing FWHM are very difficult to combine into the final image.

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 EOS 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!

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 red 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), double ionized oyxgen ([O III]) and ionized sulfur ([S II]). The square brackets indicate that these lines are forbidden.