Don't Look Directly at the Sun, Most Especially When Using a Telescope

Image: Mark Thompson

This week saw many astronomers, amateur and professional alike, jumping to solar observations to watch the transit of Mercury across the Sun. Fortunately, they all understand that looking at the Sun directly through a telescope is bad juju.

Staring directly at the Sun can cause all kinds of damage and blindness. Isaac Newton once temporarily damaged his vision by staring at the Sun for a long period. However, Newton fortunately wasn't using a telescope when this happened. 

So, what happens if you look at the Sun through a telescope (without the proper filters)? Well, Mark Thompson made this video, where he exposes a pig's eyeball to sunlight through a telescope. It's brutal!