ASTR 1000 Lecture Notes - Lecture 11: Adaptive Optics, Wavefront, Diffraction
18 Jun 2018
School
Department
Course
Professor
Class 11
Telescope Problems:
1. Physical Distortion - stress, thermal problems (heat expands, cool
contract)
•Correction: Active Optics: tug and pull on mirror to keep it the
right shape
2. Diffraction - affects resolution. It is the process by which a beam
of light or other system of waves is spread out as a result of passing
through a narrow aperture or across an edge, typically
accompanied by interference between the wave forms produced.
•Correction: bigger telescopes
3. Seeing - turbulence caused by looking through earths atmosphere
•Correction: adaptive optics: is a technology used to improve the
performance of optical systems by reducing the effect of incoming
wavefront distortions by deforming a mirror in order to compensate
for the distortion. You get rid of earths atmosphere turbulence all
together.
Light waves tend to interact
with each other. Wave diffracts
– starts to spread out.
You cannot get all the light to
fall on one point – falls into a
diffraction pattern
Example of Seeing Effect:
Example of adaptive optics.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Class 11: physical distortion - stress, thermal problems (heat expands, cool contract, correction: active optics: tug and pull on mirror to keep it the right shape, diffraction - affects resolution. You get rid of earths atmosphere turbulence all together. Light waves tend to interact with each other. You cannot get all the light to fall on one point falls into a diffraction pattern. Radio telescopes - an instrument used to detect radio emissions from the sky, whether from natural celestial objects or from arti cial satellites. They need to have a big diameter so they can measure big wavelengths. You can make an infromometer which allows you to make a cheat on the resolution side. Detectors: eyes: sketching, writing notes, records - hard to get objective view as it depends on skills of observer. Film/photography: not ef cient, glass plates: ccd - charge couple device .
