Baader IR-Pass Filter 685nm

• Baader IR-Pass Filter HWB 685nm
• Reduces the effect of seeing resulting in a much sharper image.
• Ideal for imaging and used for the luminosity channel.
• Usage: The normal spectral bandwidth is 400-700nm. This filter starts at 670nm in the deep red, just in the visual range so it can be focused correctly. At this long-wavelength spectral range the atmospheric air turbulence (seeing) has much lower impact on the sharpness. Dark structures on Mars, Jupiter the Moon and the Sun are thereby rendered much sharper. The luminosity can then be combined with RGB creating a very sharp LRGB image.
• Highly recommended for any planetary imager.
• Reflection free and optically polished.

Baader Planetarium delivers the latest tool in the planetary imager's bag of tricks. The Baader IR-Pass filter blocks wavelengths below 670 nm. At these longer wavelengths, planetary images are less disturbed by wavefront distortions in the atmosphere (seeing). By combining a luminance image taken with the IR-Pass filter, along with RGB frames, overall image sharpness is significantly enhanced. Some of the world's best amateur planetary images have been taken with this technique.

Also darkens the twilight sky background, allowing mages of moon and planets to be taken at dawn or dusk. Deep sky images reveal young hot stars in dust clouds and star forming regions.

The IR-Pass filter shares the same outstanding features as all the other Baader filters. High optical quality, Striae-free substrate, and high efficiency multicoatings result in the sharpest and highest contrast image possible.

In addtion to astronomical uses, theIR-Pass filter can be used for nature photography in the Near-IR, revealing stunning differences in plants, sky, and clouds (requires use of a camera that is sensitive to IR above 670nm, such as a modified DSLR or webcam).

Baader IR-Pass Filter (FIRP) Filter Curve

The above transmission plot is not a theoretical curve - but an actual measurement taken of a Baader IR-Pass filter.