How are pictures of the sun taken? For example, how do devices such as the Hubble Telescope take pictures of solar flares?
1 Answer
Pictures of the sun are taken with special filters.
Explanation:
While the Hubble never takes pictures of the sun, SOHO , SDO and HINODE all do, as well as a number of ground based telescopes. Usually they use a variety of interference filters, which block out all but a single wavelength (colour) of light. Each wavelength is selected to reveal particular features, such as flares and prominences.
Some also use an occulting disk, which acts like an artificial eclipse, in order to see the corona around the sun.
Amateur astronomers use two main types of filters for viewing the sun through a telescope:
White light filters, which block all light equally, are good for seeing sunspots, but not surface detail or prominences.
Hydrogen alpha filters allow only the single wavelength of red light produced by hydrogen gas (the alpha line), adn show considerable detail on the surface, but are very much more expensive than white light filters.
