Telescopes Flashcards
What is Refraction
The way that light bends when passing through an object that slows down the speed that light is traveling.
Why is refraction possible if lightspeed is a constant?
The speed of light is only a constant in vacuum, when passing through an object, electrons must vibrate to pass through, causing the speed to be impacted (like honey).
What does the angle of refraction depend on
The wavelength of the light
(this is why prisms work; they separate colors so that they each come out at a slightly different angle)
What is a converging lens?
Light (far away) comes in parallel and is bent to a focal point (e.g. Magnifying glass)
- Distant object appears UPSIDE DOWN
Illustration of ray tracing
Enlarging the image
What is a (refracting) telescope a combination of?
Converging lens and illustration of ray tracing
first lens: upside down image of a distant object
Second lens: magnification
What does the size of the light capturing object in a telescope determine?
The amount of energy (information) is gathered in and captured
What is the largest refracting telescope
Yerkes Observatory (40 in)
What is a reflecting telescope?
(Newton)
Creates focal point of bent light with a parabolic mirror
Then deflected out of the side eyepiece at a 90-degree angle
What type of telescope are radio telescopes?
Prime focus - Do NOT have a second optical lens
What is a Cassegrain reflector?
Same as a Newtonian reflector, but light is reflected out the back
What does adaptive optics mean?
Changing the shape of the mirror to compensate for the earth’s atmospheric turbulence
What makes ultraviolet telescopes different than radio and optical telescopes?
Must be in space! above that nasty meddling atmosphere
What is interferometry
cross referencing multiple telescopes to cover a larger area/ combination of waves
- works best with radio telescopes
What type of telescope is the Webb telescope? (currently in space!)
Cassegrain (can do spectroscopy)
- has to be kept cold
