We can put special filters that help to block out some of the light on the telescopes (a bit like when you put on sun glasses). These filters only let a small fraction of the light through so we can the images clearly. However, this doesn't always work and often telescopes suffer what is known as "saturation". This means that the cameras can only count so many packets of light per second. If there are more than that limit coming into the telescope, they just read the maximum all the time - i.e. they saturate! You can see in this picture: http://i.space.com/images/i/14730/i02/m9-solar-flare-jan-2012.jpg that there is a bright white region right in the middle. This is because the camera can't handle how bright this part of the image is. Notice how you can't see any detail in that region. Compare the really bright part to the lower left corner where you can see all of the detailed plasma. Hope this helps, Claire