% SF_Specification.m
% Written by Stacie Manuel

% Version History:
% June 4, 2009 - Version 1

%% Overview:
% This example script shows how to use the function SF_Spec_Calc which
% calculates a structure function specification.   

% This script allows the user to enter the polishing specification values
% for the calulation, given in terms of values for r0, percent scattering
% and wavelength and then plots the results for a telescope. The
% calculation follows the discussion by Hill in "Optical Design, Error
% Budget and Specifications for the Columbus Project Telescope" (Proc. SPIE
% 1236, 86-107 (1990)) and assumes the telescope has tilt correction.  

%% Inputs:

% 1) ro: the coherence length of the atmosphere, also known as
% Fried's parameter 
r0 = 125; % Enter number in units of cm

% 2) lambda_r0: the wavelength for which r0 is given
lambda_r0 = 500; % Enter number in units of nm

% 3) loss: due to scattering normalized to 1 (i.e. enter 0.025 for 2.5%
% scattering loss)
loss = 0.025;

% 4) lambda_loss: the wavelength for which the loss is given
lambda_loss = 500; % Enter number in units of nm

% 5) dia: the diameter of the telescope
dia = 420; % Enter the number in units of cm

%% Calculation

[x,delta]=SF_Spec_Calc(r0,lambda_r0,loss,lambda_loss,dia);

%% Plot the results

loglog(x,delta)
title('Mirror polishing specification')
xlabel('Separation between measurement points (cm)')
ylabel('RMS phase error (nm)')
legend({['r_0 = ',num2str(r0),'cm, loss = ',num2str(loss*100),'% at \lambda = ',num2str(lambda_loss),'nm']})