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The Lumicon pre-filter is a 77mm red filter which fits on the front of the SCT. The prominence filter threads into the back and provides a decent image of solar prominences, flares and sunspots. It allows for a 1.5 Angstrom bandpass near the hydrogen alpha line. Although the sky was clear around noon, and seeing seemed excellent, the prominence filter was not great today. There was a large prominence on the sun's west-southwest side as seen through the scopes. The lumicon filter allows for some fine tuning by rotating the prefilter to align with the rear filter, and also a set screw on the rear filter. This tuning made some big differences. The filter allowed for a very bright prominence, and if tuned improperly, the prominence would disappear. The internal reflection today seemed brighter than normal. I was on my lunch time and didn't spend the relaxed time necessary to allow the filter to strut its stuff. This filter does what it advertises. It allows for viewing and photographing of solar prominences and sunspots. The bandpass is too broad to allow for the images visible in Jeff's TV-85, but I'll let him tell you about those. In defense of the old orange tube, it sat in the back of the car all morning with the sun beating down. The car was very hot, and perhaps the temperature of the scope was well above ambient temperature. The filters were hot as well. But I think I just didn't take the care to set up as well as I should have. I normally see better images through this filter and scope system, and have seen very good photos others have taken. I'm still pleased with the prominence filter. I don't know if Lumicon still makes it or not. I will say Lumicon did not try to pull any false advertising with this filter. I would like to adapt it to fit the 102 and see what kind of images would be visible through it. Larry
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