Compute refraction-corrected sunrise, sunset and noon times in seconds at a given latitude, longitude and date.
Compute solar elevation, azimuthal and declination angles of the sun at every second of the day.
The code is also hosted on github.com/rdroste/sunRiseSet
sun_rise_set = sunRiseSet( lat, lng, UTCoff, date) Computes the *apparent* (refraction
corrected) sunrise and sunset times in seconds from mignight and returns them as
sun_rise_set. lat and lng are the latitude (+ to N) and longitude (+ to E), UTCoff is the
timezone, i.e. the local time offset to UTC (Coordinated Universal Time) in hours, and date is
the date in format 'dd-mmm-yyyy' ( see below for an example).
[sun_rise_set, noon] = sunRiseSet( lat, lng, UTCoff, date) additionally returns the solar noon
in seconds from midnight.
[sun_rise_set, noon, opt] = sunRiseSet( lat, lng, UTCoff, date) additionally returns the
information opt, which contains information on every second of the day:
opt.elev_ang_corr : Apparent (refraction corrected) solar elevation in degrees
opt.azmt_ang : Solar azimuthal angle (deg cw from N)
opt.solar_decl : Solar declination in degrees
sun_rise_set = sunRiseSet( ..., PLOT) If PLOT is true, plots of the elevation and azimuthal
angle are created.
lat = 47.377037; % Latitude (Zurich, CH)
lng = 8.553952; % Longitude (Zurich, CH)
UTCoff = 2; % UTC offset
date = '15-jun-2017';
[sun_rise_set, noon, opt] = sunRiseSet( lat, lng, UTCoff, date, 1);
Reverse engineered from the NOAA Excel:
The formulas are from:
Meeus, Jean H. Astronomical algorithms. Willmann-Bell, Incorporated, 1991.
Richard Droste (2021). sunRiseSet( lat, lng, UTCoff, date, PLOT) (https://www.mathworks.com/matlabcentral/fileexchange/62180-sunriseset-lat-lng-utcoff-date-plot), MATLAB Central File Exchange. Retrieved .
Hi, Works well except when the sunset or the sunrise happens the day before or after the selected day. For example when the sunset happens the day before, the code provides a value of 00:00:01 which is not correct. Does somebody know how to fix that?
Works well after I figure out what UTC was. It would be helpful to include a better description in the notes section for UTC. Have you considered adding a function to programmatically determine the UTC based off the lng, lat inputs?
I do not have the financial toolbox and was not able to use daysact() . A simple fix was to replace Line 39 with:
nDays = datenum(date)-datenum('30-dec-1899');
Also, the lines of code with trigonometric calculations can be cleaned up by using sind(), asind(), etc. functions versus rad2deg(asin(deg2rad(sin(value)))).
it's possible use date option like a vector?. I need calculate sunset/sunrise varations troughtout the year.
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