Optolong L-eXtreme Narrowband Filter Review
The Optolong L-eXtreme filter has narrow 7nm band passes in the Hydrogen alpha (Ha) and Oxygen III (OIII) lines, unlike the older Optolong L-eNhance, which also has a band pass at the Hydrogen beta (Hb) line. The Optolong L-eXtreme will block out that extra bit of light pollution by omitting the Hb line, while retaining all the detail from emission nebulae by capturing the targets in Ha and OIII.