Sky-Watcher Heliostar 76mm Hydrogen-a Solar Telescope

The Sky-Watcher Heliostar 76mm H-alpha Solar Telescope is a dedicated hydrogen-alpha solar telescope designed exclusively for observing and imaging the Sun. Rather than showing the Sun in ordinary white light, it isolates the H-alpha wavelength at approximately 656.28 nm, revealing activity in the solar chromosphere that is not visible through a conventional white-light solar filter.

The 76mm aperture provides considerably more resolving power than smaller dedicated solar telescopes, allowing the Heliostar to show fine detail across the solar disc and around its limb. Features such as prominences, filaments, active regions, plage and spicules can all become visible, giving the observer a view of a dynamic Sun that changes from day to day and sometimes from hour to hour.

At 630mm focal length and f/8.3, the Heliostar combines a useful image scale with a relatively compact optical tube. The telescope’s achromatic doublet is fully multicoated for H-alpha use and is specifically designed around the narrow wavelength being observed. The optical system is therefore not intended as a general-purpose night-time telescope; it is dedicated to H-alpha solar observation.

At the heart of the Heliostar is Sky-Watcher’s Solis Etalon Technology. The etalon provides a native bandpass of less than 0.5 Å, allowing the telescope to produce high-contrast views of solar chromospheric detail without requiring a second etalon. This is particularly valuable when observing structures on the surface of the Sun, where contrast can be critical for seeing fine detail.

The integrated Trifid Tuner provides mechanical adjustment of the etalon. By applying controlled pressure to the etalon plates, the tuner allows the observer to adjust the system to the H-alpha emission line and optimise the view. This makes it possible to fine-tune the telescope as observing conditions and the features being viewed change.

Focusing is handled by a 2-inch dual-speed Crayford focuser. The dual-speed mechanism provides coarse and fine focusing, making it easier to achieve precise focus when viewing small solar structures or when using a camera.

The Heliostar is supplied with an 11.5mm blocking filter incorporated into the dedicated solar diagonal. This blocking filter is an essential part of the telescope’s solar safety system, and Sky-Watcher specifically states that the supplied solar diagonal must be used. The telescope also includes an integrated Heliostar solar finder, allowing the Sun to be located without looking directly towards it through a conventional finder.

A 20mm 70° 1.25″ eyepiece is included, providing approximately 31.5× magnification with the 630mm focal length. This gives a useful starting point for observing the full solar disc and its larger-scale features. A smartphone adapter is also included, allowing a smartphone to be positioned over the eyepiece for straightforward solar imaging.

The telescope comes with mounting rings and a V-style dovetail, making it compatible with mounts equipped with a suitable V-style saddle. A clip-on Sun shade is supplied to reduce stray light around the eyepiece area during observation, while the hard-shell carrying case provides a convenient way to transport and store the complete system.

The Heliostar 76mm is therefore a complete dedicated H-alpha observing system rather than simply an optical tube. With the solar finder, blocking-filter diagonal, eyepiece, smartphone adapter, mounting hardware, sun shade and carrying case included, it can be equipped for visual solar observation and basic solar imaging straight out of the box.

Important: The Heliostar 76mm is a dedicated solar telescope and must only be used with the supplied solar-filtering components correctly installed. Sky-Watcher states that the 11.5mm blocking filter in the supplied diagonal is part of the telescope’s safety system and that the telescope must not be used with another type of diagonal. Incorrect solar observing practices can cause serious and permanent eye damage.