Astronomik ProPlanet 742 IR Clip-Filter for Sony alpha cameras

The Astronomik ProPlanet IR 742 Clip-Filter for Sony alpha 7 cameras is used for planetary imaging and can be inserted into the camera body within seconds.

The ProPlanet IR 742 only allows infrared light with wavelengths of more than 742 nm to pass. In this wavelength range, the effects of seeing are significantly lower than in the visible spectrum of the human eye. This allows much sharper images than are usually obtained from your device and location. Another advantage is that the sky background of advanced dawn is dark and so the filter even allows photography of the planets and the moon at daylight.

Especially for Mars photography, this filter lets pass the spectral range with the greates detail.

Using telescopes with at least 150 mm (6") is recommended.

The Challenge:

Do you own a Sony alpha 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!

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:

The Clip-Filter are sucessfully tested with the bodies Sony Alpha 7, 7r and 7s. (Astronomik will test other/future models and add them here.)

The manufacturer has made a short video which shows installation and removal of the clip-filter for Sony Alpha:



The filters are not suitable for Sony alpha 3000 to 6500 or Sony alpha NEX cameras.

Other uses:

♦ Besides astrophotography the filter allows you to get stunning results in nature photography. If a Clip Filter is used in an MC-modified DSLR, you get tremendous results imaging the flora. The filter cuts off the part of the spectrum where Chlorophyll looks green and shows its high reflectivety in the near infrared. If trees are photographed in spring and summer under blue skies, you get stunning images with white trees and clouds in front of a near black background.
♦ Darkens the background during twilight.
♦ Imaging of bright planets, stars and comets by day.
♦ Imaging of young stars in dust clouds and stellar nurseries.

Alternatives:

When the seeing is very bad and the instrument is 250 mm (10") or larger, the Astronomik ProPlanet IR 807 may be the better choice.

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.

♦ 1 filter in plastic box