00:01
Okay, question 22 is asking us to design a flow chart that shows the progress of astronomical observation that led to the development of the ccd camera.
00:17
So astronomy started out with just the simple telescope like the one galileo used back in 1610, which was just a simple refractor, and that was basically a long tube that had a lens and an eyepiece, but such a telescope was rather limited in its observation capabilities.
00:57
These telescopes with such a small aperture only had a small light gathering capability, and in order to see more objects and more objects in better detail, they needed to create something larger.
01:15
So we went from this in 1610 to getting bigger telescopes a century later.
01:26
What i'm going to draw right now is a diagram of the 40 -foot telescope, william herschel used.
01:37
This was a telescope that was housed in a cottage in slow england, and it basically was a giant reflector, not a refractor like galileo used.
02:01
As you remember, reflectors had better observing capabilities than refractors because they don't suffer from chromatres, because they don't suffer from chromatic.
02:13
Aberration like refractors do.
02:19
Anyway, we still found that creating giant telescopes wasn't necessarily making things better.
02:31
Larger telescopes made the objects appear larger, but they didn't give finer details.
02:37
Things still looked very faint through these telescopes.
02:43
What we later learned is that the issue wasn't with the telescopes, it was with the limited capability of the human eye.
02:53
So we needed to find a way to compensate for that.
02:58
This telescope finished construction in about 1787.
03:04
Now, the first advancement toward something better than just pure telescopes was astrophotography, and it was in 1840 that an astronomer named john draper created the first astronomical photograph.
03:28
And what i'm going to be showing you here is among the earliest photographs taken of earth's moon.
03:43
Now, this isn't the photograph john draper took...