Lunt LS80MT/B1800 Multi-Purpose (Day/Night) Apochromatic Telescope

The Lunt LS80MT/B1800 is built for observers who want to explore the Sun in a level of detail that a conventional night-time telescope cannot provide. Working at the H-alpha wavelength of 656.28 nm, the telescope is designed to show structures and activity in the Sun’s chromosphere, including prominences, filaments and active regions. With its 80mm solar aperture and individually verified 0.45 Å bandpass, the LS80MT provides a dedicated platform for detailed H-alpha solar observation.

At the heart of the telescope is Lunt’s internally mounted pressure-tuned H-alpha etalon. The Doppler True tuning system uses barometric pressure adjustment to fine-tune the etalon, allowing the observer to optimise the H-alpha view as solar features change. Rather than simply observing a featureless solar disc, the narrow H-alpha bandpass makes the constantly changing structure of the Sun the subject of observation.

The B1800 blocking filter has an 18mm clear aperture, giving this configuration a substantially larger illuminated field than the smaller blocking-filter options. This is particularly useful for solar imaging, especially when working with cameras with larger sensors, while also providing a generous field for visual observation.

The optical system is based around a professional-grade FLP53 ED doublet with an 80mm aperture and 560mm focal length. In its H-alpha configuration, the telescope is a dedicated solar instrument; remove the H-alpha module and the LS80MT becomes a conventional 80 mm f/7 ED apochromatic doublet refractor for night-time observation and astrophotography. This modular architecture gives the telescope a much broader role than a dedicated solar instrument while retaining its specialist H-alpha capability.

The 2-inch dual-speed rack-and-pinion focuser provides precise focusing, with a 10:1 fine adjustment and compatibility with the ZWO EAF for motorised focusing. The telescope can also be expanded with Lunt’s optional double-stack module, producing a combined H-alpha bandpass below 0.28 Å for observers looking to further narrow the solar bandpass.

The LS80MT/B1800 is therefore a telescope for spending time with the Sun rather than simply looking at it: a premium H-alpha instrument for observing the constantly changing solar surface, with the added flexibility of becoming a full 80 mm ED refractor when the Sun sets.