BP468-10 Bandpass Filter(CWL=468nm,FWHM=10nm)

Astronomy: He-II (Ionized Helium) Imaging

The strongest specific match for this filter is the observation of Ionized Helium (He-II).

• Target: The He-II emission line is located precisely at 468.6 nm.
• Use Case: This filter allows astrophotographers and researchers to isolate the structure of Wolf-Rayet stars, high-excitation Planetary Nebulae, and supernova remnants. Because the He-II line is very faint, the narrow 10 nm bandwidth is critical to block out light pollution and Moon glow while capturing the specific 468.6 nm signal.

Recommended Light Sources

• Celestial Targets (Wolf-Rayet Stars, Planetary Nebulae): These objects naturally emit the specific 468.6 nm He-II line due to extreme ionization; the advantage is that this natural emission acts as a unique tracer for high-energy structural details, allowing the filter to block all competing terrestrial light (light pollution) and broadband moonlight to maximize signal contrast.

Fluorescence Microscopy (Excitation Filter)

In bio-imaging, 468 nm is a standard "Blue" excitation wavelength used to energize green-emitting fluorophores.

• Target: Exciting fluorophores such as GFP (Green Fluorescent Protein), FITC, Lucifer Yellow, or Acridine Orange.
• Use Case: While 488 nm is the peak for GFP, 468 nm is a common alternative excitation point (on the "shoulder" of the absorption curve) used to separate excitation light from the emission signal more effectively, or when using specific LED sources.

Recommended Light Sources

• High-Power Blue LED (465 nm or 470 nm) - Spectral Efficiency & Contrast: These LEDs emit a narrow spectrum that closely aligns with the 468 nm passband, ensuring maximum energy transfer to the fluorophores (like GFP) while minimizing heat generation and background "noise" (stray light) that is common with broadband mercury arc lamps.