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These new filters serve particularly the needs of the digital photographer imaging the solar system with electronic cameras or Webcams (with IR-block filter removed) at long-focus telescopes.
The Astronomik planet IR pro CCD filter offers two main advantages:
- The filter passes only light within a range, that makes seeing become much lesser apparent than in the visual. In other words: The picture becomes substantially steadier and thus also sharper in large telescopes.
- The filter is particularly useful for Mars CCD photography, because it opens at wavelengths, in which the surface details show the highest contrast.
Further advantages to the well-known RG filters from Schott:
- better suppression of seeing as with Schott RG 665
- steeper flanks (shorter exposure times)
- multi coated surface (better contrast)
- optical thickness identically to other Astronomik filters (parfocal)
- transmission adjusted for perfect use with amateur telescopes
Why two different kinds of filters?
Solving the problem of decreasing optical resolution at higher Wavelengths was the main goal of the Astronomik team. So you are able to make use of the better imaging quality caused by lower seeing effects. Besides this the nearly unpredictable near IR sensitivity of most CCD and CMOS Sensors gave this issue a higher complexity. Using the results of a number of different tests made by the team, confirmed by amateur experiences throughout the country, an optimal filter transmission curve could be determined.
Comparing the filters:
single frame with IR+UV -cut-filter
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processed image with IR+UV cut filter
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single frame with ProPlanet 742 filter
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processed image with ProPlanet 742 filter
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The 742 filter is designed for telescopes of smaller diameter. At this wavelengths most electronic cameras have still almost their full efficiency. The majority of wavelengths troubled by seeing effects, is blocked.
The 807 filter is perfect for telescopes starting at 8" diameter. At this wavelengths most electronic cameras are less sensitive. This effect is compensated by the larger aperture. But here however the seeing becomes much lesser apparent than with the shorter-wave passing filter.
| Facts: |
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| Main application |
For planetary- and lunar photography these filters block the whole visual light. The pass the near IR where the seeing is much better than at visual wavelenghts. You´ll get better images. Especially for mars these filters enhance the part of the spectrum where dark and bright details have maximum contrast. |
| How it works |
Blockung des sichtbaren Lichtes, welches besonders stark für das Seeing anfällig ist. |
| visual observation |
not usefull |
| classical photography |
not usefull |
| CCD-photography |
The filter is optimized for telescopes with more than 5" (~12,5cm) diameter. Use it with a webcam or video camera withou a IR-blocker ! The focal ratio for optimum results is f/25 .... f/40 |
| Main parameters
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Transmission up to 98 %
Blocking at 400 - 720 nm
Transmission >95 % above 760nm |
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