Telescopes and Instruments Flashcards
What is the equation for the energy of light as a particle?
E = hf
What EM radiation has the largest wavelength?
Radio.
How do you draw a ray diagram for a camera?
Lens at a distance from focal plane.3 rays drawn at same angle to lens. One through middle does not change direction. Other two meet the focal plane at the same point as the centre ray.
How do you find the image size from a camera ray diagram?
Draw perpendicular rays as well as angled rays and the image size is the distance between the two focal points.
How is a telescope different from a camera?
It has an extra eye-piece between the detector and the aperture.
What is the equation for the magnification factor of a telescope?
M = α2/α1 = f1/f2.
What can limit resolution?
Diffraction effects of observing through a finite aperture.
What is the Airy Disc?
Point source of diffraction rings, with width of the central maximum Δα (rad) = 1.22λ/D
What is the requirement for two objects to be resolved?
The sources need to be separated by at least their Airy disc to be resolved.
Why is the atmosphere a problem?
It absorbs, refracts, is turbulent, contains humidity, dust and molecules.
What are good sites for telescopes to be situated at?
Dark, low humidity, low turbulence, good seeing conditions etc.
Why would you observe stars from space?
You can access wavelengths blocked by the atmosphere such as UV and shorter wavelengths.
