Last night I tried out this anti-fringing filter on my Skywatcher 120mm f5 refractor. The moon,two nights past first quarter, and Saturn were my targets. Eyepieces used were a 4mm Radian (150X), and a 2.5mm Vixen Lanthanum (240X). Seeing conditions were fair with some "rippling" of the images. The moon without the filter at 150X was plenty contrasty with lots of detail. Naturally there was some violet coloration. With the V_Block in place, the violet hue was replaced with a yellow-green color. I could detect no increase in contrast and the image was not as sharp as without the filter. Switching to the Lanthanum without the filter the false color was much more noticeable, but the craters and mountains were still quite sharp. The overall image color was more pleasing with the addition of the filter, but still, I did not see any increase in contrast, and I could especially see at higher magnification that the lunar details were softened by the addition of the filter.
Using the same eyepieces and the V-Block on Saturn, the results were pretty much the same as with the moon: the only differences I could see that the filter made were a slight yellow-green hue, and the image was not as sharp as without the filter. This is a brand-new filter; examined under a bright light and an 8X loupe it appeared to be very clean. I really see no reason why the filter should reduce resolution in the image unless the filter glass is not perfectly plano-parallel, or is not seated squarely in its mount. I could see no evidence of this latter possibility on close examinaton of the filter. Then again, the filter is manufactured in Korea and the finish of the cell at least is not on a par of what one would expect from Japan or China. Anyone else used one of these with better results than I had?
Using the same eyepieces and the V-Block on Saturn, the results were pretty much the same as with the moon: the only differences I could see that the filter made were a slight yellow-green hue, and the image was not as sharp as without the filter. This is a brand-new filter; examined under a bright light and an 8X loupe it appeared to be very clean. I really see no reason why the filter should reduce resolution in the image unless the filter glass is not perfectly plano-parallel, or is not seated squarely in its mount. I could see no evidence of this latter possibility on close examinaton of the filter. Then again, the filter is manufactured in Korea and the finish of the cell at least is not on a par of what one would expect from Japan or China. Anyone else used one of these with better results than I had?
