William Optics VR-1 Violet Reducer Filter

5.0 Excellent Chromatic Aberration Reduction Filter

Effectively reduces the violet haze caused by CA, appears to sharpen the image slightly.

None.

I own a large aperture, short focus achromatic refractor. While I primarily bought it to observe deep-sky objects, for which it provides excellent views, I occasionally enjoy using it to split double stars or observe a planet or two. This is where the scope suffers from some serious chromatic aberration. All bright objects from stars to planets to license plates are surrounded by a violet halo and an inability to come to a truly sharp focus.

William Optics’ VR-1 filter is just one of many “minus violet” filters available that are designed to cancel out light from the violet end of the spectrum, effectively reducing the violet haze around bright objects. It comes in two sizes to screw onto eyepieces or diagonals of either 1.25 or 2-inches in diameter.

The VR-1 filter is very effective at reducing the chromatic aberration to the point of making even my refractor much more enjoyable for viewing planets or bright stars. It even helps to reduce visual “noise,” a muddling of the image also caused by CA, making the image actually appear sharper.

Unlike some other minus-violet filters, the VR-1 does not cause any distracting color shift in the telescope’s image. Even on bright planets like Jupiter or Venus, the color appears natural without any yellowish tinge.

In conclusion, William Optics’ VR-1 violet reduction filter does an excellent job of allowing an achromatic refractor to provide an image that’s closer to that of an apochromatic refractor.