% IAP 2007 Introduction to MATLAB: Programming Practice
% Instructor: Violeta Ivanova, violeta@mit.edu

% Exercise Two: Writing a Program

% Write a MATLAB program to compute the Sun's zenith and azimuth in Boston.
% Boston's is located at Latitude 42.3580N; Longitude 71.06W; Altitude 49 ft.
% Use functions UNITS and SUN_POSITION from MATLAB Central.

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function x = SunBoston(year, month, day, hour, min, sec)

% A. COMPUTE TIME
% Use structure TIME as described in help text for function SUN_POSITION. 

nowBoston.year = year;
nowBoston.month = month;
nowBoston.day = day;
nowBoston.hour = hour;
nowBoston.min = min;
nowBoston.sec = sec;
nowBoston.UTC = -5

% B. COMPUTE ALTITUDE
% Use function UNITS to convert 'ft' to 'm'. 

altitude = units(49, 'ft', 'm');

% C. COMPUTE LOCATION
% Use structure LOCATION as described in help text for function SUN_POSITION.

Boston.latitude = 42.358;
Boston.longitude = -71.06;
Boston.altitude = altitude

% D. COMPUTE SUN POSITION IN BOSTON
% Use function SUN_POSITION. 

Sun_Boston = sun_position(nowBoston, Boston)