Also known as the Horsehead Nebula filter, the Lumicon 2" Hydrogen-Beta Filter isolates only the hydrogen-beta line of the spectrum (486nm) in a narrow pass-band just 9 nm wide, providing maximum contrast.
The 1.25" filters employ industry-standard 1.125" x 42 tpi threads (except for Questar/Brandon, which use a thread pattern unique to Questar). The 48 mm filters employ industry-standard 48 x 0.75 mm threading, which thread into 2" eyepieces. All larger filters use the given size with 0.75 mm pitch (e.g. a 72 mm Minus Violet filter has 72 x 0.75 mm threads).
Recommended for 12" or larger telescopes
Now, you can view extremely faint nebulous objects such as the Horsehead, Cocoon and California Nebulae; In many cases, the Lumicon Hydrogen-Beta Filter is the ONLY way to view these objects
To ensure that your Lumicon filter remains the world's best, the strictest quality control standards are employed throughout the production process
Each Lumicon Hydrogen - Beta Filter is individually inspected and proudly inscribed with the percentage of light transmittance of the H-Beta emission line