Lecture 5 Flashcards
Blueshift
Objects moving toward us
Redshift
Objects moving away from us
How does light tell us the rotation rate of an object?
The width of an objects spectral lines can tell us how fast it is rotating
Refraction
Refraction is the bending if light when it passes from one substance into another
Your eye uses refraction to focus light
Focusing Light
Refraction can cause parallel light rays to converge to a focus
Image Formation
The focal plane is where light from different directions comes into focus
The image behind a single (convex) lens is actually upside down
Focusing Light
Digital cameras detect light with charge - coupled devices (CCDs)
A camera focuses light like an eye and captures the image with a detector
The CCD detectors in digital cameras are similar to those used in modern telescopes
two most important properties of a telescope
Light collecting area
Angular Resolution
Light Collecting Area
Telescopes with a larger collecting area can gather amount of light in a shorter time
Angular resolution
Telescopes that are larger are capable of taking images with greater detail
What tells us the light collecting area
Telescopes Diameter
Angular resolution
Is the minimum angular separation that the telescope can distinguish
Diffraction limit
The limit on angular resolution is known as the diffraction limit
Two basic designs of telescopes
Refracting telescope
Reflecting Telescope
Refracting telescope
Focuses light with lenses
