Altair 2" 8 nm 540 nm Solar Continuum Contrast Booster

Altair 2" 8 nm 540 nm Solar Continuum Solar Booster

The Altair 2" Solar Continuum filter enhances sunspots, granulation, and fine photosphere detail. For use with Baader AstroSolar Film or Herschel wedge.

The Solar Contrast Booster works by filtering out UV, IR and visual wavelengths except for a narrow 8 nm FHWM green band at 540 nm. This greatly increases the contrast of solar features when viewed with the naked eye, colour or monochrome camera, revealing more detail around sunspots and granulation (fast-developing solar convection cells) in the solar photosphere. Highly recommended for use with either APM 2" Herschel Wedge or Baader AstroSolar Film.

Note: Do not insert the filter before your Herschel prism or it will melt, it should be placed just in front of the camera or eyepiece, using the 2" nosepiece by means of the M48x0.75 thread.

Why is transmission centred on 540 nm wavelength?

540 nm is a very desirable wavelength for imaging and observing the sun. The Solar Contrast Booster filter improves performance of any telescope optics such as refractors, Newtonian reflectors, Maksutovs, Dall-Kirkhams, Cassegrains, and SCTs. It´s especially recommended with Frauenhofer achromatic refractors and short focal length ED doublets, because their optimum performance peaks in this green wavelength by design. In fact, not only achromats, but most ED triplet and apochromatic refractors traditionally have peak performance at 540 nm wavelength, where the human eye shows best sensitivity. 530-540 nm is not only the traditional "design benchmark wavelength" for most telescope optics, and also that of most high end interferometry equipment used to configure and optimise telescope lenses. Most colour and monochrome CMOS cameras also have peak sensitivity and resolution in green! Colour CMOS cameras in particular have an RGGB pixel layout with two green pixels for every one blue and red pixel, for an obvious increase in resolution. The are therefore many benefits in isolating this wavelength to capture those fleeting moments of good seeing.

IMPORTANT SAFETY INFORMATION: DO NOT USE THIS FILTER FOR DIRECT SOLAR OBSERVATION!

It must be used together with a professional solar filter or Herschel wedge with max. 0.024% transmission placed BEFORE this filter. For reflecting telescopes, we recommend Baader AstroSolar film on the front of the telescope, then screw the filter into a filter holder, camera, or eyepiece. For refractors, the filter should be positioned just in front of the camera or eyepiece with a Herschel Wedge in place (a front filter as with reflecting telescopes is also possible). Do not use this filter without a suitable solar pre-filter in place, because it will permanently damage your eyes or camera!

- Filter
- Protective box

Safety informations: PDF Download