Red 610nm longpass filter with steep absorption edge.
Filters the H-alpha line from the visible spectrum.
Blue and Green lights is almost completely filtered blocked increasing contrast between the light and dark bands on Jupiter and Saturn.
Most interesting filter to use for observing the polar caps of Mars.
An optimum filter for daily observation of all the planets.
Multi-coated for max contrast – no reflections, scatter or dimming.
Planeoptically polished to within 30 seconds of arc for a sharp image at high magnification with non-ageing sealed coating edges.