Sun

H-alpha (Hα) is a specific deep-red visible spectral line in the Balmer series with a wavelength of 656.28 nm in air and 656.46 nm in vacuum; it occurs when a hydrogen electron falls from its third to second lowest energy level. H-alpha light is the brightest hydrogen line in the visible spectral range. It is important to astronomers as it is emitted by many emission nebulae and can be used to observe features in the Sun’s atmosphere, including solar prominences and the chromosphere.

This kind of photography requires a special filter that is quite expensive and the narrower is the bandwidth more expensive is the filter. A complete telescope for H-Alpha exists for amateur photography. I have been lucky to use one of this equipment for a short time.

It is really very difficult to take beautiful photos of the sun with this technique. I did my best but results are far from acceptable one. Anyway, here there are some attempts to take the sun in H-alpha.

Some prominences are visible in this photo and the granular surface of the sun with two sunspots. The magnetic activity is visible close the sunspots

ISS Zarya (International Space Station) in low orbit transits many times per day above our skies but sometimes the transit is exactly between your position on the Earth and the sun or the moon. It is possible to take a photo of this transit and see the shadow of the Station quite clearly.

Since the distance from the Earth of the ISS is not always the same, the subject may appear bigger if the transit is in a lower orbit or smaller if it is on a higher orbit.

High orbit ISS transit

Lower orbit ISS transit

The Sun may appear smooth and brilliant. But often is scattered with dark spots. Sunspots are areas that appear dark on the surface of the Sun. They appear dark because they are cooler than other parts of the Sun’s surface, about 6500 degrees. Solar flares are a sudden explosion of energy caused by tangling, crossing or reorganizing of magnetic field lines near sunspots.

It is possible to catch them with a normal camera but (VERY IMPORTANT!!!) with an Energy Rejection filter that reduces the energy of the sun light. If you point the camera directly to the Sun serious injuries may occur to the eyes and of course to the camera!