Lunt B1800 Hydrogen Alpha Blocking Filter with KG3 glass

For sale is a Lunt 18mm Hydrogen Alpha solar blocking filter with 2 inch straight through tube  and modified with a KG3 IF/UV/IR filter. The KG3 glass replaces the original BG38 glass and provides  better IR cutoff performance. The original BG38 blue glass filter is included.

This B1800 blocking fillter is used in conjunction with Lunt Hydrogen Alpha solar filter etalons and is not meant as a stand alone solar filter. Please refer to the Lunt Solar web site for details and proper use.