Lunt LS100MT H-Alpha Solar Telescope - Premium PLUS Kit

A Foundation of Optical Excellence: The 100mm ED Doublet

At the heart of the LS100MT is a 100mm f/7.14 apochromatic doublet objective. The use of FPL51 Extra-low Dispersion (ED) glass corrects for chromatic aberration, producing a sharp, high-contrast image free of false color. This optical purity is not only critical for isolating the narrow Hydrogen-alpha wavelength but also allows the LS100MT to serve as a high-performance nighttime telescope when the H-alpha module is removed.

Precision Tuning without Compromise: The Internal Pressure-Tuned Etalon

Lunt’s Doppler True Tuning system uses air pressure to adjust the refractive index within the primary etalon cavity, allowing you to shift the bandpass precisely onto the 656.28nm line. Unlike mechanical tilt-tuning which can introduce off-axis aberrations, pressure tuning keeps the etalon perfectly parallel to the light path. This results in a more uniform, higher-contrast image across the entire field of view, a critical advantage for both visual observation and full-disk imaging.

Revealing the Surface: The SFPT Internal Double-Stack Module

This Premium PLUS kit includes the internal SFPT double-stacking module, the key to its enhanced performance. Adding a second etalon in series with the first narrows the final bandpass from ≤0.35Å to a remarkable <0.28Å. This dramatic reduction in out-of-band light significantly increases contrast on the solar disk, causing the intricate, web-like structure of filaments and the bright mottling of plage around sunspots to stand out with startling clarity.

With the double-stack engaged, you are no longer just seeing features on the sun, you are observing their structure. A simple filament resolves into a multi-stranded, twisting rope of plasma held in place by magnetic fields. The view shifts from a two-dimensional disk to a dynamic, three-dimensional surface, which is the ultimate goal of dedicated solar observation.

Full-Disk Views without Vignetting: The B1800 Blocking Filter

The blocking filter is a non-negotiable safety and performance component, and this kit includes the 18mm B1800. The larger aperture is matched to the telescope's 714mm focal length to provide a fully illuminated field for both eyepieces and imaging sensors. With the B1800, you can capture the entire solar disk, including towering prominences on the limb, without the dimming or vignetting at the edges that a smaller blocking filter would cause.

Critical Focus for Fine Detail: The Dual-Speed Focuser

Observing the sun is a high-magnification discipline where precise focus is everything. The LS100MT employs a robust, dual-speed rack and pinion focuser that eliminates image shift and backlash. The 10:1 fine focus knob allows you to make the minute adjustments needed to snap the finest spicules on the limb or the delicate texture within a sunspot's penumbra into perfect, sharp relief.

One Telescope, Day or Night: The Modular Design

The "MT" in LS100MT stands for Modular Telescope. The entire Hydrogen-alpha assembly, including the red etalon housing, can be removed from the main optical tube. With optional accessories, you can convert the 100mm ED doublet into a first-rate refractor for nighttime planetary and deep-sky viewing, a white-light solar scope using a Herschel wedge, or a Calcium-K instrument. This versatility makes the LS100MT a long-term investment in your observing, not just a single-purpose instrument.

The primary trade-off for this level of performance and versatility is the need for a stable, high-capacity mount. The weight and length of the LS100MT require an equatorial mount in the EQ5/CG-5 class or higher to provide a steady, vibration-free platform for the high-magnification views it is designed to deliver.

Choosing Your Lunt 100MT Configuration

Lunt offers the LS100MT in several packages, allowing you to choose the right entry point for your observing goals.

• Standard Kit: This package includes the single-stack ≤0.35Å etalon and a B1200 blocking filter. It provides excellent views of solar prominences and basic surface detail, serving as a powerful entry into professional-grade solar astronomy.
• Enhanced Kit: The Enhanced kit upgrades the blocking filter to the larger B1800, optimizing the system for imaging and ensuring a wider, fully illuminated field of view. It is the right choice if you plan to move into solar photography.
• Premium PLUS Kit: This is the ultimate configuration. It includes the B1800 blocking filter and the crucial SFPT internal double-stack module. For the observer who wants the highest possible contrast on surface features like filaments and active regions, this kit delivers the most detailed and dynamic view possible from a 100mm platform.