• Question: Why is looking through a telescope at the sun more harmful than usual? Isn't it just enlarging the size of the sun - not the brightness?

    Asked by conn207 to Antonia, Douglas, Hugh, Matt, Tom on 24 Jun 2010 in Categories: .
    • Photo: Matthew Hurley

      Matthew Hurley answered on 13 Jun 2010:

      All the light normally falls over a large area. When you focus the light into a small spot there is a lot more energy that can burn you eyes.

    • Photo: Douglas Blane

      Douglas Blane answered on 24 Jun 2010:

      Good question. It’s doing both.

      Think of a hand-held telescope that has the small end about the same size as your eye and the other end a good bit bigger.

      Without the telescope you get all the light that would go through the small end in your eye. With the telescope you get all the light that goes into the large end in your eye.

      But it’s worse than that, because all the light from the sun that goes into the large end gets focused by the telescope into a spot on your retina that’s much smaller than the small end.

      So all that energy coming in the large end is concentrated on one wee spot of your very sensitive retina. And burns a hole clean through it.