Lecture 12

Lecture 12 - ASTR100Lecture12 19/02/200913:59:00 Review...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
ASTR 100 Lecture 12 19/02/2009 13:59:00 Review     Discussing telescopes *Conundrum, radio astronomy, why did it start with an amateur?  Universal Design issues  o Light gathering Proportional to D squared of the objective o Image quality  Purpose of a telescope is to form an image and study/magnify that Optical Telescopes Image Quality  o Seeing o Manufacturing limitations  o Diffraction limits related to diameter of the telescope, fuzziness due  to diffraction. (the facet edges)  Amount of Fuzziness is proportional to the wavelength of the wave compared to  the diameter Lambda/D Resolving power: D/lambda {Better for large D and small lambda}  (Ability to see detail)  Manufacturing Limitations     Practical consequence of seeing -only have to make the mirror/lens so that manufacturing defects are significantly  less than the diffraction problems. 
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
DO THIS effectively perfect telescope  Accuracy of the surface ~ lambda/10 Yellow light 5 x 10 -7 m                                                                                 10  ~2 MILLIONTH OF AN INCH  Have been able to do this for ~200 years  key word : “Diffraction limited optics”  The Seeing     Primary limiting factor of any earth-based telescope  The seeing is the measure of the turbulence in the atmosphere, “Twinkling” of  stars Fuzzing out the image Limitation caused by the motion of the earth’s atmosphere  The seeing Limitation on image quality due to atmosphere and only a limit on  EATH BASED telescopes.  Ex. Hubble Space telescope D = 2.5m Palomar D = 5m Keck D = 10m Diffraction Limits (each is only 2 rimes better)  HST is about 20 times better image quality than Paloma
Background image of page 2
Last 10-15 years
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 11

Lecture 12 - ASTR100Lecture12 19/02/200913:59:00 Review...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online