Lunt Internal 0.35A Double Stack Module for LS130MT
Lunt Internal Double Stack Module for LS130MT Telescopes
This Lunt Solar Systems internal double stack module for LS130MT measures ≤0.35Å FWHM per etalon, down from ~0.55Å. As of 2026, Lunt has improved their etalon manufacturing specification to deliver ≤0.35Å FWHM bandwidth. This is a 40% improvement over the previous ~0.55Å design. When used in double-stack systems, this translates to system bandwidth of around 0.22Å.
This improvement is achieved through tighter coating tolerances and refined manufacturing procedures, and very production etalon is verified on Lunt’s 1.5-meter Sciencetech scanning monochromator at 656.28 nm, and the plate parallelism confirmed on their Zygo Verifire interferometer (factory certified by Zygo).
For existing Lunt systems, adding a new etalon to a previous-generation double-stack achieves approximately 0.27Å.
The result of this upgrade in this Internal Double-Stack module is an enhanced view of the Sun that reveals more detail, whether observing visually or imaging. This internal double-stack filter is user-installable and comes with a pressure tuner for Doppler tuning. The double stack module is compatible with Lunt LS130MT telescopes.