Lunt 60mm Ha Etalon Filter
- 60mm Aperture
- 0.4Å Bandpass H-Alpha Filter
- Tilt-Tuned Etalon
- Double-Stacks Lunt 60mm Scopes to <0.28Å
- Front-Mount Filter Design
The Lunt 60mm Ha Etalon Filter delivers the high-contrast views of a verified 0.4Å bandpass through its 60mm front-mounted etalon. This filter serves a dual role, capable of either converting a standard refractor into a dedicated solar telescope or double-stacking a compatible Lunt 60mm system to achieve a bandpass of less than 0.28Å for maximum surface detail.
This filter's core is a 60mm unobstructed etalon, precision-tuned to a 0.4Å bandpass at the hydrogen-alpha wavelength. Unlike filters with estimated specifications, every Lunt LS60FHa is individually tested using precision metrology equipment to guarantee its performance. The tilt-tuning mechanism allows you to shift the bandpass slightly, providing the ability to dial in the highest contrast on solar features experiencing Doppler shift, such as filaments and active regions.
For owners of a Lunt LS60MT or LS60THa telescope, the LS60FHa acts as a powerful double-stacking upgrade. By mounting this second etalon to the front of your existing telescope, you narrow the system's final bandpass to under 0.28Å. This dramatic reduction in bandwidth significantly increases contrast across the solar disk, revealing finer texture in the chromosphere and rendering filaments with a striking, three-dimensional appearance against a darker sky background.
The LS60FHa can also serve as the primary objective filter for a custom solar telescope built around your own nighttime refractor. When paired with a compatible Lunt blocking filter, this front-mounted 60mm etalon transforms your refractor into a high-resolution H-alpha instrument. Because it mounts on the front, it is easily removable, allowing you to quickly return your telescope to its original configuration for night sky observing.
Using the LS60FHa as a standalone filter requires a Lunt Blocking Filter, which must be purchased separately. The blocking filter is a critical safety component that removes harmful UV and IR radiation and is essential for the etalon to function correctly. You must select a blocking filter appropriately sized for your telescope's focal length.
A single-stacked LS60THa provides excellent views, but double-stacking to achieve a <0.28Å bandpass dramatically increases contrast. When viewing a flare or filament, the feature will appear darker and more defined against a more uniform, darker solar disk. This enhanced contrast often reveals subtle structural details that are washed out at a wider bandpass.
The tilt-tuning mechanism physically angles the etalon relative to the incoming light. This slight tilt shifts the filter's central wavelength, allowing you to "tune" into the precise wavelength of solar features that may be slightly blue- or red-shifted due to their velocity relative to us (Doppler effect). This allows you to maximize contrast on specific active regions or filaments.
No. The LS60FHa has a clear aperture of 60mm. When placed on the front of any telescope, it acts as a 60mm aperture stop. Your 100mm refractor will perform as a 60mm H-alpha solar telescope, with its resolution and light-gathering ability limited to that of a 60mm instrument.
Installation is straightforward. The LS60FHa is designed to thread directly onto the front of compatible Lunt 60mm telescopes, such as the LS60MT and LS60THa. No tools are required, and the process typically takes less than a minute, making it easy to add or remove based on your observing goals for the day.
It means that Lunt Solar Systems individually tests each LS60FHa etalon with precision metrology instruments to confirm it meets the 0.4Å specification. This provides assurance that you are receiving a filter that performs to the stated level of contrast, rather than one based on a design estimate or batch testing.
| SKU | LS60FHaP |
| Product Type | Front-Mount H-Alpha Solar Filter |
| Aperture | 60mm |
| Bandpass | 0.4Å |
| Tuning | Tilt-Tuned Etalon |
| Double-Stack Bandpass | <0.28Å (with compatible Lunt scope) |
| Compatibility | Lunt LS60MT, Lunt LS60THa |