Astronomik ProPlanet 642 BP Clip-Filter for Sony alpha cameras

The Astronomik ProPlanet IR 642 BP is the lastest addition to the family of Astronomik ProPlanet IR-pass filters. As a Clip-Filter, it can be inserted into the camera body within seconds.

The filter thrills because of its wide range of applications for daylight IR photography, high-resolution lunar and planetary imaging and for taking beautifull and deep images of H-alpha regions when used for astrophotography.

"BP" are short for "Bandpass": The filter gives you a 200 nm spectral window from 642 nm to 842 nm. Contrary to the other two ProPlanet filters it blocks the longer infrared. Together with the Astronomik ProPlanet 742 and the ProPlanet 807, you can now have three choices to match your needs when imaging in the IR. The Astronomik ProPlanet 642 BP will be the right choice for the best image quite often!

With the Astronomik ProPlanet 642 BP, you get three filters in one product: depending on the camera, it is a fine tool for daylight IR photography with a digital camer, reduces seeing and enhances contrasts in high-reslution planetary and lunar imaging and is a economically-priced H-alpha filter for the start into deep-sky astrophotography of H-alpha nebulae.

How it works:

The ProPlanet IR 642 reduces dusturbing atmospheric affects when creating monochrome planetary and lunar videos. This is achieved through a transmission window where the wavelangth range has to fullfill a couple of requirements:

♦ the unsharpness which is caused by vertical motion of air in the atmosphere (seeing) are minimized
♦ the camera sensitivity is used best
♦ the wavelength range is tuned to the resolution and correction of the telescope.

The filter is designed for (astronomical webcams without built-in IR blocking filter or MC-modified DSLR cameras with video function. The wavelength range which passes the filter is a mixture of deep red and short wave infrared. Thus the filter is usable for colour imaging with the Astronomik L-RGB filter set for replacing the L filter under bad seeing, so that clearly sharper and less deformed images can be achieved. This enhances the usability of the images in postprocessing considerably. By including the H-alpha and [S II] lines, it is a wide-band, but economically priced alternative to pure line filters of those wavelengths.

The focal range for getting optimal results can be found between f/1 and f/30.

Deep-sky astrophotography:

At the well-known H-alpha emission line, the ProPlanet 642 BP reaches its maximal transmission of almost 100%. Whereas all photons of the beautiful H-alpha regions hit the sensor, shorter wavelengths with the bulk of the light pollution are blocked. If using an astronomically modified camera, the bandwidth is reduced to 40 nm. The result is an enormous gain in contrast due to a darker sky background.

Daylight IR imaging:

One initial point when develloping the ProPlanet 642 BP was daylight imaging with (modified) digital cameras.

For normal photography, an IR blocking filter is mounted directly in front of the sensor in the camera, as the sensors are sensitive up to more than 1100 nm. By removing this built-in filter, a camera can be used for the very interesting IR photography.

The Astronomik ProPlanet 642 BP starts transmittion in the deep-red spectral range and lets pass all light up to 842 nm. Thus you get images perfectly suitable for channel selection and allows for an outstanding color separation in postprocessing, as the starting wavelength of 642 nm, combined with blocking long-wavelength delivers especially constrasty images.

Other uses:

The Planet IR 642 Pro BP is suitable exclusively for cameras without IR blocking filter.

Especially with colour cameras without IR blocking filters, it is the best to take monochrome images, as the Beyer matrix is not defined in IR and the camera gets "color-blind". The Astronomik Planet IR 642 Pro BP is not suitable for solar observation or photography, even if used with a sun filter.

Alternatives:

For luminance exposures (monochrome cameras) or colour imaging in the visual range, we recommend the Astronomik L filter. For pure IR exposures, we recommend the Astronomik ProPlanet 742 IR pass-filter or Astronomik ProPlanet 807 IR pass filter.

If the seeing is mediocre and if the telescope is smaller than 10" (250 mm), we recommend the use of the Astronomik ProPlanet IR 742.

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

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.

♦ 1 Filter in plastic box