Sky-Watcher Heliostar 76Ha Solar Telescope

A Dedicated H-Alpha Prominence Telescope

The Heliostar 76Ha is a prominence telescope: its front and rear filters allow only monochromatic 656.28 nanometer light from hydrogen atoms to pass and block other wavelengths, which allows the observation of quite active prominences in the H-alpha band.

The H-Alpha Filter System

The telescope uses several technologies to protect the eye during observation: an infrared thermal ray reflection film, a special filter to block heat, and a filter to block UV light, which also block stray light that affects observation. The bandwidth is under 0.5Å and the solar image size 6mm.

The etalon sits in its own housing behind the objective, and a solar zenith prism takes the eyepiece. The blocking filter is 11.5mm, in the 1.25" diagonal. The lenses are H-alpha fully multicoated.

ISO 12312-2 Solar Filters and Safety

The permanently mounted glass solar filters conform to and meet the transmission requirements of ISO 12312-2, Filters for Direct Observation of the Sun.

The Sun can only be observed in prominence (H-alpha) mode with the certified solar filters in place, and observing the Sun in any other mode will cause permanent and irreversible damage to the eyes and the equipment. Do not dismantle the telescope: there are no user serviceable parts inside.

Focusing, Tuning and the Solar Guider

The focuser is a 2" dual-speed Crayford (Sky-Watcher USA). The manual says to loosen the set screw and turn the focusing knob for fast focusing.

Then fine-tune the adjusting bolt left and right until the prominence in the eyepiece is nearly sharp. Place the telescope outside for more than half an hour before every use, so the temperature inside and outside the etalon housing is constant, which improves observing and imaging.

Point the telescope using the solar guider: adjust the mount until no projection appears in the guider, then until the shadow sits in the middle of the pinhole, and finally until the shadow is centered on the projection glass. The guider centers the Sun by projection, without looking through the telescope.

Smartphone Adapter

A smartphone adapter is included for photographing through the eyepiece; the manual refers you to the smartphone adapter manual for details.

Mounting

The tube weighs 3.8 kg (8.4 lb) and comes with mounting rings on a V-style dovetail bar, so use a mount with a Vixen-style saddle and a payload rating that covers it. Attach the dovetail to the saddle and lock the knobs, then install the zenith prism and eyepiece, fasten them with the knurled screws and remove the cap.

Tube and Included Accessories

The tube is aluminum and about 600mm (24") long. Sky-Watcher USA's package includes a hard carrying case and the following:

• Solar guider: centers the Sun by projection, without looking through the telescope.
• Light shield: clips on; after the telescope is adjusted, attach it for more comfortable viewing.
• Blocking diagonal: the 1.25" solar zenith prism (11.5mm blocking filter). Also included: a 20mm 70° eyepiece (32x), a smartphone adapter, and two mounting rings with carry handle on a V-style dovetail bar.

Care

Always place the dust caps on the telescope when not in use.

Clean the optics only with a lint-free cloth, and only once dust has accumulated: small amounts on the front lens do not affect performance. Do not use abrasive materials or aggressive chemicals, avoid touching the front element, never submerge the telescope or any parts in water, and never dismantle it.