00:01
Question 17 is asking why we haven't built any refractors larger than the one at the yerkes observatory, which has an aperture of one meter.
00:11
Okay, so we're going to draw a diagram of a refracting telescope.
00:18
It would look something like this, an eyepiece at one end, and then a long skinny tube with a lens.
00:37
At the other end.
00:39
Now, one of the shortcomings of a telescope like this is if you look at a diagram of a lens that would be found in a refracting telescope, as light hits the edges of the lens, the light gets refracted out at the edges.
01:13
So we would end up having chromatic aberration is what it's called at these edges.
01:25
That's where the blue light gets refracted more than red light, and the image ends up having those red edges.
01:37
So one disadvantage of a larger refracting telescope would be this chromatic aberration, but there are a few other disadvantages of a telescope.
01:51
A larger refracting telescope of this nature.
01:55
With larger resolution, more detail can be seen in images, but with ground telescopes, they come at a disadvantage of being below earth's atmosphere...