Sky-Watcher Heliostar 76mm H-Alpha Solar Telescope
Hydrogen alpha solar observation uncovers the incredible dynamics of the Sun's surface far beyond what a white-light solar filter can offer. From solar prominences in the Sun's limb (often mistakenly called "flares"), to active sunspot regions, bright plage patches, surface granulation, undulating and meandering plasma filaments, and much more, the solar system's star is yours to capture in stunning views and images.
just in time to reach solar maximum in 2025!
Double the fun
The Heliostar 76mm Hα solar telescope provides incredible double stack performance for the price of an etalon filter. No need for expensive dual stack systems, Heliostar 76Hα is tuned to
Safety information
The Heliostar 76mm H-Alpha Sky-Watcher Sky-Watcher Solar Telescope has been laboratory tested here in the United States to meet ISO 12312-2 safety standards. Each telescope is tested one by one in the real Sun to ensure that each unit is ready for safe solar observing right out of the box.
This is a dedicated solar telescope and will not provide views or images of anything but the Sun. Use extreme caution when observing the Sun, as improper use and practices can cause serious and even permanent eye damage.
In addition, the 11.5mm locking filter on the diagonal of the removable eyepiece is part of Heliostar's safety features. Do not use with any other type of diagonal.
what's in the box?
The Heliostar 76Hα includes a collection of accessories to ensure it is ready for observing right out of the box. The telescope includes mounting rings, V-dovetail, Heliostar solar finder, dual-speed Crayford focuser, 11.5mm locking filter, clip-on sunshade, 20mm 70° 1.25" eyepiece, and a camera phone adapter for taking quick photos and sharing them with your friends. All inside a rugged carrying case, so you're ready to take your Heliostar 76 anywhere. A perfect complement to the Sky-Watcher SolarQuest mount, the ultimate in portable solar telescopes!
Hydrogen alpha technology
Hydrogen alpha (Hα) solar telescopes are specialized instruments used to observe the Sun at a specific wavelength of light-656.3 nm-which corresponds to the red line of the Balmer series of the hydrogen emission spectrum. This wavelength is essential for studying in great detail solar phenomena such as prominences, filaments, sunspots and solar flares. Unlike standard white-light telescopes, which capture the broad spectrum of the Sun, Hα solar telescopes provide a window into specific solar activity in the chromosphere, a layer of the solar atmosphere located just above the photosphere.
Etalon filter technology
At the heart of most solar Hydrogen Alpha telescopes is the etalon filter, a high-precision optical device that isolates the Hα wavelength from the rest of the light emitted by the Sun. An etalon is a type of interferometer, consisting of two parallel mirrors separated by a precise distance. The etalon works by reflecting light several 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 and block all other wavelengths. The key to the etalon's performance lies in its ability to tune the wavelength it transmits. This is achieved by adjusting the distance between the mirrors or by slightly tilting the etalon, which changes the interference conditions. This tuning is crucial because the Sun's Hα emission can change slightly due to Doppler effects as the material moves across the Sun's surface and atmosphere.
There are two main types of etalon filters used in solar telescopes: single etalon and double etalon systems.
Single etalon: A single etalon filter usually has a narrower bandwidth, which provides high contrast for detailed solar observations, but at the cost of limiting the field of view. This makes single etalon systems well suited for observing small, high-contrast features such as prominences or filaments.
Dual etalon: A dual etalon system uses two etalon filters in tandem to improve wavelength selectivity, reduce overall bandwidth, and improve image contrast and clarity over a wider field of view. Dual etalon systems are preferred for more detailed solar surveys because they can provide both a sharper image and better tuning, allowing for a more accurate representation of solar dynamics.
Solis Etalon Technology: Sky-Watcher's Solis technology allows the Heliostar to achieve a bandpass of 0.55A without the costly expense and complexity of a second etalon to achieve the same performance. This allows the observer to obtain detailed images of the solar disk right out of the box without any additional 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 band. The Trifid tuner uses three support veins to provide secure tuning for the etalon.
Technical Specifications
Optical Specifications
Achromatic Optical Design
H-alpha lens coating with full multi-coating
Lens design Doublet
Optical quality Diffraction limited (1/4 wave)
No collimating cell (self-aligning cell)
Primary aperture 76 mm
F ratio 8.3
Focal length 630 mm
Blocking filter size 11.5 mm
Solar image size 6 mm
Bandpass
Mechanical specifications
Focuser type Crayford
Focuser size 2" Focuser
Focuser Single or double speed Single or double speed Double speed
Compression Ring No* (Diagonal only)
Material OTA Aluminum
Optical tube length (cm) 61
Optical tube weight (Kg) 3.8
mounting rings? Mounting rings
Dovetail type Vixen
Accessories
Eyepieces 20mm 70º 1.25" eyepiece
11.5mm H-alpha locking diagonal 1.25" eyepiece
Camera adapter Mobile phone adapter
Additional accessories Parasol
Heliostar solar finder included
Digital PDF manual
Carrying case Yes
Observation Information
Dawes limit 1.52
Rayleigh limit 1.84
Magnitude limit 11.88
Minimum magnification 7x
Maximum magnification 150x
Magnification with eyepieces included 32x
Intended use Solar (visual and imaging)
