For my Astrophotography geek fans...... - Chicago Astronomer | Facebook
A Guide to Imaging Filters
Amazon.com : SVBONY SV132 Telescope Filter H-Beta Filter 25nm 1.25 inches Eyepiece Filter for Horsehead Nebula California and Cocoon Nebulae in Dark Skies : Electronics
Astronomik H-beta Filter
Test review: Baader CMOS-optimized 5.5nm H-Beta Narrowband Filter / Baader Planetarium Blog Posts