train:lectures:telescopeoptics

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train:lectures:telescopeoptics [2024/03/24 12:15] – Roy Proutytrain:lectures:telescopeoptics [2024/03/24 12:54] (current) – Roy Prouty
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 This FWHM is what we use to report our effective angular resolution. The FWHM (similar to the standard of deviation, $\sigma$) is measured in pixels in image space, but is most useful to discuss in terms of seconds of arc (''). This FWHM is what we use to report our effective angular resolution. The FWHM (similar to the standard of deviation, $\sigma$) is measured in pixels in image space, but is most useful to discuss in terms of seconds of arc ('').
  
 +Determine the effective angular resolution of the "Original Airy" profile shown below. Assume the ASI 432 is placed on the main scope.\\
  
-====Diffraction Limited====+[{{:train:lectures:20240321_airyseeing.png?800|Single Airy Profile with fit. Sum of many Airy Profiles with fit.}}] 
 +Consider a telescope unencumbered by pesky atmosphere and is therefore observing an Airy Disk when observing a point source. Take the $x$ axis to be the number of pixels relative to the center of the profile and estimate the Angular Resolution.
  
  
-[{{https://www.astronomynotes.com/telescop/twmountn.gif|Better Seeing Geometry}}]\\ 
  
-[{{https://www.astronomynotes.com/telescop/twinkle.gif|Poor Seeing Geometry}}]\\ 
-Consider a telescope unencumbered by pesky atmosphere and is therefore observing an Airy Disk when observing a point source. Take the $x$ axis to be the number of pixels relative to the center of the profile and estimate the Angular Resolution. 
  
  
-Determine the effective angular resolution of the "Original Airy" profile shown below. Assume the ASI 432 is placed on the main scope.\\+====Seeing Limited====
  
-[{{:train:lectures:20240321_airyseeing.png?800|Single Airy Profile with fit. Sum of many Airy Profiles with fit.}}] 
  
 +[{{https://www.astronomynotes.com/telescop/twmountn.gif|Better Seeing Geometry}}]\\
 +
 +[{{https://www.astronomynotes.com/telescop/twinkle.gif|Poor Seeing Geometry}}]\\
  
-====Seeing Limited==== 
 Due to the turbulent and inhomogeneous atmosphere, rays of light have many opportunities to refract upon impinging a volume of atmosphere with differing optical properties (think: index of refraction from Snell's Law). These refraction events have the effect of displacing the center of the Airy Profile. By the Central Limit Theorem, the sum$^1$ of many displaced Airy Profiles approaches a Gaussian Profile. This gives us confidence in our choice of a Gaussian PSF (though there are better-matching PSF models; e.g., Moffat Profile). Due to the turbulent and inhomogeneous atmosphere, rays of light have many opportunities to refract upon impinging a volume of atmosphere with differing optical properties (think: index of refraction from Snell's Law). These refraction events have the effect of displacing the center of the Airy Profile. By the Central Limit Theorem, the sum$^1$ of many displaced Airy Profiles approaches a Gaussian Profile. This gives us confidence in our choice of a Gaussian PSF (though there are better-matching PSF models; e.g., Moffat Profile).
  
-Determine the effective angular resolution of the "Sum of 3000 Disp. Airys" profile shown below. Assume the ASI 432 is placed on the main scope.+Determine the effective angular resolution of the "Sum of 3000 Disp. Airys" profile shown above. Assume the ASI 432 is placed on the main scope.
  
 An optical system whose angular resolution is limited by these repeated refraction events is said to be **Seeing Limited**. An optical system whose angular resolution is limited by these repeated refraction events is said to be **Seeing Limited**.
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 ====CODE==== ====CODE====
-[[https://colab.research.google.com/drive/1SocmlQtnegS2GoyTZN7gaM840_eHzxcI?usp=sharing|Google Colab for Detector Basics I]]+[[https://colab.research.google.com/drive/1SocmlQtnegS2GoyTZN7gaM840_eHzxcI?usp=sharing|Google Colab for Telescope Optics II]]
  
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