Sunspots (visible in H-alpha images, white light images, magnetic field images) - Sunspots are dark areas on the Sun that form where magnetic field lines enter the Sun. Sunspots are dark because they are cooler than the surrounding areas of the Sun. The sunspots may be surrounded by bright regions called plages. Since this project is being carried out at Solar minimum, there will probably only be small sunspots, or none at all.
Sunspots, Image credit: NASA
Solar corona (visible in coronagraph images, ultraviolet images) - The Solar Corona is the outermost layer of the Sun (named because it appears as a crown surrounding the star), and will appear as bright regions arching and streaming outward, as the outer edges of the Corona become the Solar wind that engulfs our Solar System.
The corona, Image credit: NASA
Coronal holes (visible in ultraviolet images) - Coronal Holes are dark areas of the Corona that are less dense and less hot. They can cover large areas of the Sun.
Arrows point to coronal holes, Image credit: NASA
H-alpha features (visible only in H-alpha images) - Certain noteable features can only be seen in H-alpha light. These features include:
Granulation - the mottled appearance of the solar disk as seen in Hydrogen Alpha. It will appear as bright patches separated by darker boundaries. Granulation is an illustration of convection in the Sun, the process by which heat flows from the interior to the surface of the Sun. When you are looking at the granules, you are looking at hot blobs of matter that are rising to the surface of the Sun from the even hotter interior, cooling off, then sinking back into the interior again. Since granulation is the process by which heat flows from the center of the Sun to its exterior, it is present even at solar minimum.
Granulation, Image credit: BBSO
Prominences - bright clouds seen at the edge of the Sun against the black of outer space. Often, these appear as bright arches. They are bright because they are hot and made of hydrogen, so according to Kirchoff’s Second Law, they glow in the spectral lines of hydrogen. An amazing thing about prominences is that they are held up against the strong gravitational force of the Sun by magnetic forces.
Prominences, Image credit: BBSO
Filaments - look like long, dark lines on the solar disk . They can only be seen with a hydrogen alpha filter. They represent prominences which are seen in absorption against the light of the Sun, rather than in emission against the dark sky at the solar limb.
Filament, Image credit: BBSO
Solar Flares - (rare) one of the most exciting phenomena to see. Flares are huge explosions on the surface of the Sun. The effects of these explosions can sometimes be detected at Earth, one astronomical unit away. If you see a flare, it will appear as a starlike bright point on the Sun, almost always in the vicinity of a sunspot. It will increase to maximum brightness and fade away in a matter of a few minutes. The tremendous energy associated with solar flares comes from the energy stored in solar magnetic fields.
