HELIOSTAR-76Hα

Double the Fun

The Heliostar 76mm Hα Solar Telescope provides incredible double stack performance for the price of one etalon filter. There is no need for costly double stack systems, Heliostar 76Hα is tuned to <0.5Å natively providing rich surface detail and with its 76mm aperture high resolution viewing and imaging is easily obtainable.

Safety Information

The Sky-Watcher Heliostar 76mm H-Alpha Solar Telescope has been lab tested here in the United States to meet the ISO 12312-2 safety standards. Each scope is tested one by one on the actual Sun to make sure each unit is ready for safe solar viewing right out of the box.

This is a dedicated solar telescope and will not provide views or images of anything except for the Sun. Please use an abundance of caution when observing the Sun as incorrect usage and practices can result in serious and even permanent eye damage.

Also, the 11.5mm blocking filter in the removable eyepiece diagonal is part of Heliostar's safety features. Do not use with any other type of diagonal.

What's In the Box?

The Heliostar 76Hα features a collection of accessories to ensure you are ready for safe solar viewing right out of the box. The telescope includes mounting rings, V-style dovetail, Heliostar solar finder, dual speed Crayford focuser, 11.5mm blocking filter, clip on sunshade, 20mm 70° 1.25” eyepiece and a camera phone adapter to snap quick pictures to share with your friends. All of this is housed inside a rugged carrying case, so you are ready to take your Heliostar 76 anywhere. A perfect match for the Sky-Watcher SolarQuest mount for the ultimate, portable solar telescope setup!

Hydrogen Alpha Technology

Hydrogen Alpha (Hα) solar telescopes are specialized instruments used to observe the Sun in a specific wavelength of light—656.3 nm—which corresponds to the emission line in the “A” alpha absorption band of the Balmer series. This wavelength is critical for studying solar phenomena like spicules, prominences, filaments, sunspots, and solar flares in great detail. Unlike standard white-light telescopes, which capture the Sun's broad spectrum, Hα solar telescopes offer a window into specific solar activity in the chromosphere, a layer of the Sun's atmosphere located just above the photosphere.

Etalon Filter Technology

At the heart of most Hydrogen Alpha solar telescopes lies the etalon filter, a highly precise optical device that isolates the Hα wavelength from the rest of the Sun’s emitted light. An etalon is a type of interferometer, consisting of two parallel mirrors separated by a precise distance. The etalon works by reflecting light multiple times between the mirrors, selectively allowing only wavelengths that satisfy specific resonance conditions to pass through.

In the case of Hα solar telescopes, the etalon is designed to transmit light at the Hα wavelength while rejecting all other wavelengths. The key to the etalon’s performance lies in its ability to tune the wavelength allowed through the filter. This is achieved by adjusting the distance between the mirrors or by slightly tilting the etalon, which changes the angle of incidence. Tuning the etalon to each side of the central wavelength is needed because local changes in atmospheric pressure change the refractive index of your local air mass.   The Sun's emission at Hα can also shift slightly due to Doppler effects as violent explosions in the Sun's chromosphere can cause solar plasma to move at enormous speeds. 

There are two primary types of etalon filters used in solar telescopes: single etalon and double etalon systems.

Traditional H alpha solar telescopes have been sold in two basic configurations; single etalon and the very costly double etalon systems.  It has always been a choice of the single etalon's brighter prominences or more contrast of surface features from an additional etalon.  The second etalon has the unfortunate consequence of reducing the brightness of the system by a whopping 40%.

Solis Etalon Technology: Sky-Watcher's all new Solis technology allows the Heliostar to achieve a 0.55A bandpass without the costly expense and complexity of a second etalon to achieve the same or better performance without reducing the brightness significantly. This allows the observer to see very high contrast detailed images of the solar chromosphere right out of the box without any further expense.  

Trifid Tuner: Inside the Heliostar is Sky-Watcher's Trifid tuning system. This tuner applies physical pressure to the etalon plates allowing the observer to reach the desired Hydrogen emission line. The Trifid tuner uses three support veins to provide a secure tuning for the etalon without stressing any peripheral systems.

Please enjoy solar astronomy safely!