The Optolong L-eXtreme filter is a light pollution dual band filter designed to drastically reduce the effect of light pollution. Its two passing bands isolate the nebulae emissions in H-Alpha (red) and OIII (green-blue).
The advantage of the L-eXtreme filter is that there is no transmission between the H-Alpha and OIII lines as there a
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Jim · January 14, 2026
Fast shipping - great service and very helpful advice from the Testar Team
Jerome · May 13, 2025
Quality product. Impeccable and fast 3 day turnaround service by Testar.