ao - ForOT Optical Turbulence Forecasts
ao - ForOT Optical Turbulence Forecasts
ao - ForOT Optical Turbulence Forecasts
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
DETRIMENTAL EFFECTS BY THE ATMOSPHERE<br />
ON ASTRONOMICAL OBSERVATIONS<br />
“SPECKLE IMAGE” OF STAR<br />
NOTICE: (i) speckle size = size of Airy disk of telescope<br />
(ii) speckles colored (diffraction phenomena)<br />
(iii) number of Speckles N sp<br />
≈ (D/r o<br />
) 2 . D = Telescope Diameter<br />
r 0<br />
= “Fried Parameter” = 10 cm for 1” seeing @ 500nm<br />
D = 10m N sp<br />
≈ 10000<br />
(iv) speckle image changes rapidly (≥ 10 Hz)<br />
(v) for D ≤ r 0<br />
Airy disk N = 1<br />
(one speckle) which “dances”<br />
(2) REFRACTION<br />
(a) atmospheric dispersion/refraction<br />
(b) atmospheric turbulence “seeing” limits resolution<br />
(c) atmospheric turbulence “scintillation/twinkling”<br />
limits photometry<br />
ESO/Paranal<br />
MOON<br />
NOTICE: (i) image motions<br />
(ii) “Iso-Kinetic Patch”<br />
[(iii) “Iso-Planatic Patch”]
Change language