Customers have repeatedly pointed out to us that the combination of the Moon & Skyglow Filter and the Fringe Killer produces amazingly colour-corrected images on Billi refractors. Unfortunately, there have also been complaints about reflections occurring with this combination. With this filter, you can counteract this problem. It produces a virtually colour-neutral image without the blue and red halo that so disturbingly reduces image contrast in cheap refractors.
The Fringekiller blocks about a third of the blue light. The transmission in red and green light is 100%. The resulting loss of light over the entire spectrum is only about 12%.
The semi-apo filter blocks more than 25% in blue and red light. The proportion is lower in green, but about 30% of light is lost across the entire spectrum. But the colours are once again neutral, except for a slight green tint. The light reducing effect of the semi-apo filter is about half a stop.
