The 2" Baader Solar Continuum Filter 7.5nm (540nm) from Alpine Astronomical is a narrow-band photosphere filter for solar observation in white light. It provides the highest contrast in the photosphere of the sun. The filter works as a monochromator: suppressing the effects of atmospheric turbulence and delivering images that are significantly sharper.
Lens systems, including those of apochromatics, catadioptrics, or eyepieces, are traditionally optimized for the spectral range around 540nm since this is where our eye has the highest sensitivity. This narrowband filter, therefore, blocks everything with the exception of the spectral range in which a lens optic works most sharply and with the highest contrast. The effect is greatest on achromatic lens telescopes, but there is also an effect on apochromatic telescopes, catadioptric systems, and even pure mirror systems by reducing air turbulence. As a monochromatic filter, it is ideal for use on monochromatic cameras and can even provide a tremendous gain on pure color systems.
This is not a solar filter and requires the use of a primary broadband or narrow-band solar filter to prevent permanent eye damage, up to and including blindness.
- Increased contrast, matched for typical CMOS quantum efficiency and s/n ratio
- Reflex-Blocker coatings, for largest ever freedom from halos, even under most adverse conditions concerning aux-optics
- Identical filter thickness to existing standards, with utmost care for parfocality
- Blackened edges all around, with filter-lead-side-indicator in the form of a black frontside outer rim, to additionally eliminate any reflection due to light falling onto the edge of a filter
- Each filter is coated individually, with a sealed coating edge, not cut out of a larger plate with coatings left exposed
- Life-Coat: Hard coatings to enable a non-aging coating for life, even in a most adverse environment