Transcript 10-02RayleighCriterion - TuHS Physics Home Page 1.1

Rayleigh Criterion
Contents:
•Diffraction patterns
•The Rayleigh criterion
An opening can make an
interference pattern too
Rayleigh Criterion
 = 1.22
b
 = Angle of resolution (Rad)
 = Wavelength (m)
b = Diameter of circular opening (m)
(Telescope aperture)
the bigger the aperture, the smaller the
angle you can resolve.
Central maximum of one is over
minimum of the other
Rayleigh Criterion
 = 1.22
b
 = Angle of resolution (Rad)
 = Wavelength (m)
b = Diameter of circular opening (m)
Rayleigh Criterion
1|2
TOC
What is the angular resolution of the 100 inch
(2.54 m) diameter telescope on the top of Mt
Wilson? (use 550 nm as the wavelength)
(uh 550 nm = 550 x 10-9 m)
 = 1.22
b
 = ?,  = 550 x 10-9 m, b = 2.54 m
 = 2.64173E-07
2.6 x 10-7 radians
W
What diameter telescope do you need to resolve
two stars that are separated by 1.8 x 1011 m, but
are 3.0 × 1017 m from us? (use 550 nm as the
wavelength)
(AU, 32 LY)
hint  = s/r = (1.8 x 1011 m)/(3.0 × 1017 m)
 = 1.22
b
 = 6.00 x 10-7,  = 550 x 10-9 m, b = ?
b = 1.12 m
1.1 m
W