[25March2017] Update: For brothers and sisters in Indonesia or any country below the equator, thanks to Reza's comment, the code now works correctly.
[18January2012 Update: I refined the code to make it easier and more elegant to use]
[06July2011 Update: I found this page http://praytimes.org/calculation#Implementation ]
This idea came to me when a friend of mine was asking for an 'offline database' for prayer times. I searched for algorithms to make my own database and almost all search results lead to the same algorithm. And all codes are divided into two categories: a simple but approximate one, and a complicated but precise one. I tried with the complicated one to understand it but it needs more time because of its nested functions and unfortunately it is not a priority right now. So I went with the easy one as a start.
One thing I noticed is that every person is trying to make the ultimate use of the framework he is working on (mostly dotNet). But come on, it is all about calculations. Why don't you make a code that can be easily converted from one language/platform to another? That's why I wanted to make that code. It has a major problem till now as it produces times later than my Egyptian calendar up to 5 minutes !!! Only later not earlier.
[18January2012 Update: I refined the code to make it easier and more elegant to use]
[06July2011 Update: I found this page http://praytimes.org/calculation#Implementation ]
This idea came to me when a friend of mine was asking for an 'offline database' for prayer times. I searched for algorithms to make my own database and almost all search results lead to the same algorithm. And all codes are divided into two categories: a simple but approximate one, and a complicated but precise one. I tried with the complicated one to understand it but it needs more time because of its nested functions and unfortunately it is not a priority right now. So I went with the easy one as a start.
One thing I noticed is that every person is trying to make the ultimate use of the framework he is working on (mostly dotNet). But come on, it is all about calculations. Why don't you make a code that can be easily converted from one language/platform to another? That's why I wanted to make that code. It has a major problem till now as it produces times later than my Egyptian calendar up to 5 minutes !!! Only later not earlier.
Anyways, here is the code, and I hope I can reach better results in the near future (insha'a Allah).
The parameters needed are:
 Year/Month/Day of the desired day.
 Longitude/Latitude/Time Zone of the desired place.
 Fajr Twilight/ Esha Twilight which differ in calculations from one country to another.
Organization

Angle of the sun under the Horizon (Fajr)

Angle of the sun under the Horizon (Isha)

Region

University Of Islamic Sciences,

18 Degrees

18 Degrees
 
15 Degrees

15 Degrees

Parts of the
 
Muslim World League

18 Degrees

17 Degrees

Europe, The Far East, Parts of the

Umm AlQura Committee

19 Degrees

90 minutes after the Sunset Prayer
120 minutes (in Ramadan only) 
The

Egyptian General Authority of Survey

19.5 Degrees

17.5 Degrees

Africa,

The only library used in this function was
#include <math.h>to use the trigonometric functions (sin, cos,...)
The function takes the data of Year/Month/Day/Longitude/Latitude/TimeZone/FajrTwilight/IshaTwilight plus 6 references to double variables (Fajr/SunRise/Zuhr/Asr/Maghrib/Isha). These 6 variables are the ones to return data into. I also added some supporting functions to help in some number conversions (for example, Radians to Degrees and vise versa).
//convert Degree to Radian double degToRad(double degree) { return ((3.1415926 / 180) * degree); } //convert Radian to Degree double radToDeg(double radian) { return (radian * (180/3.1415926)); } //make sure a value is between 0 and 360 double moreLess360(double value) { while(value > 360  value < 0) { if(value > 360) value = 360; else if (value <0) value += 360; } return value; } //make sure a value is between 0 and 24 double moreLess24(double value) { while(value > 24  value < 0) { if(value > 24) value = 24; else if (value <0) value += 24; } return value; } //convert the double number to Hours and Minutes void doubleToHrMin(double number, int &hours, int &minutes) { hours = floor(moreLess24(number)); minutes = floor(moreLess24(number  hours) * 60); } void calcPrayerTimes(int year, int month, int day, double longitude, double latitude, int timeZone, double fajrTwilight, double ishaTwilight, double &fajrTime, double &sunRiseTime, double &zuhrTime, double &asrTime, double &maghribTime, double &ishaTime) { double D = (367 * year)  ((year + (int)((month + 9) / 12)) * 7 / 4) + (((int)(275 * month / 9)) + day  730531.5); double L = 280.461 + 0.9856474 * D; L = moreLess360(L); double M = 357.528 + (0.9856003) * D; M = moreLess360(M); double Lambda = L + 1.915 * sin(degToRad(M)) + 0.02 * sin(degToRad(2 * M)); Lambda = moreLess360(Lambda); double Obliquity = 23.439  0.0000004 * D; double Alpha = radToDeg(atan((cos(degToRad(Obliquity)) * tan(degToRad(Lambda))))); Alpha = moreLess360(Alpha); Alpha = Alpha  (360 * (int)(Alpha / 360)); Alpha = Alpha + 90 * (floor(Lambda / 90)  floor(Alpha / 90)); double ST = 100.46 + 0.985647352 * D; double Dec = radToDeg(asin(sin(degToRad(Obliquity)) * sin(degToRad(Lambda)))); double Durinal_Arc = radToDeg(acos((sin(degToRad(0.8333))  sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude))))); double Noon = Alpha  ST; Noon = moreLess360(Noon); double UT_Noon = Noon  longitude; //////////////////////////////////////////// // Calculating Prayer Times Arcs & Times // ////////////////////////////////////////// // 2) Zuhr Time [Local noon] zuhrTime = UT_Noon / 15 + timeZone; // Asr Hanafi //double Asr_Alt =radToDeg(atan(2 + tan(degToRad(abs(latitude  Dec))))); // Asr Shafii double Asr_Alt = radToDeg(atan(1 + tan(degToRad(abs(latitude  Dec))))); double Asr_Arc = radToDeg(acos((sin(degToRad(90  Asr_Alt))  sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude))))); Asr_Arc = Asr_Arc / 15; // 3) Asr Time asrTime = zuhrTime + Asr_Arc; // 1) Shorouq Time sunRiseTime = zuhrTime  (Durinal_Arc / 15); // 4) Maghrib Time maghribTime = zuhrTime + (Durinal_Arc / 15); double Esha_Arc = radToDeg(acos((sin(degToRad(ishaTwilight))  sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude))))); // 5) Isha Time ishaTime = zuhrTime + (Esha_Arc / 15); // 0) Fajr Time double Fajr_Arc = radToDeg(acos((sin(degToRad(fajrTwilight))  sin(degToRad(Dec)) * sin(degToRad(latitude))) / (cos(degToRad(Dec)) * cos(degToRad(latitude))))); fajrTime = zuhrTime  (Fajr_Arc / 15); return; }
So, if I take Cairo as an example:
 Date: 1812012
 Longitude: 30.2
 Latitude: 30
 Time Zone: +2
 Fajr Twilight: 19.5
 Esha Twilight: 17.5
double fajr, sunRise, zuhr, asr, maghrib, isha; calcPrayerTimes(2012,1,18, 30.2, 30, 2, 19.5, 17.5, fajr, sunRise, zuhr, asr, maghrib, isha);
Note that these prayer times are still "double" and should be converted to a time format. I made the doubleToHrMin function (you can find it before the calcPrayerTimes fnction) which splits the number into Hours and Minutes. It takes the double and two references to int variables. Here is how to use it:
int hours, minutes; doubleToHrMin(fajr, hours, minutes);
Now you have the prayer time as Hour/Minute to use it however you want.
So, in brief:
 I first add the above code block to my code, then use it whenever I want like this example:
double fajr, sunRise, zuhr, asr, maghrib, isha; calcPrayerTimes(2012,1,18, 30.2, 30, 2, 19.5, 17.5, fajr, sunRise, zuhr, asr, maghrib, isha); int hours, minutes; doubleToHrMin(fajr, hours, minutes); std::cout << "Fajr: " << hours << ":" << minutes << std::endl; doubleToHrMin(sunRise, hours, minutes); std::cout << "Sunrise: " << hours << ":" << minutes << std::endl; doubleToHrMin(zuhr, hours, minutes); std::cout << "Zuhr: " << hours << ":" << minutes << std::endl; doubleToHrMin(asr, hours, minutes); std::cout << "Asr: " << hours << ":" << minutes << std::endl; doubleToHrMin(maghrib, hours, minutes); std::cout << "Maghrib: " << hours << ":" << minutes << std::endl; doubleToHrMin(isha, hours, minutes); std::cout << "Isha: " << hours << ":" << minutes << std::endl;
(view the full prayer times example in this online IDE)
I hope it is useful to someone looking for the pure algorithm with no framework dependencies, and I hope I come back to it one more time to see the problem of these extra resulting minutes.
Resources:
جمعية الفلك بالقطيف
Muslim Programmers & Designers Community
Tanzil.info (1),(2)
PrayTime.info
IslamCity.com
IslamWare.com
jazaka allaho khayran
ReplyDeleteYou are welcome :)
DeleteCan someone please help me on how to do this code on codeblock and run to compile please as i am trying keep failing ,, Jazakallah khair
DeleteHi.
DeleteI'm terribly sorry for the very late reply. Here is the same code in a complete example in an online C++ editor: https://ideone.com/sqNLrg
can you please put all this together? i mean i'm a little confused about how to arrange all this code (i'm still a beginner at programming)
ReplyDeleteYou are totally right, I made it in a hurry so it is somehow confusing. I promise to edit this entry and make it much more easier. It will be finished by this weekend insha'a Allah.
DeleteI made some changes plus a code example. I guess it is now more friendly. :)
DeleteAssalamualaikum, from Malaysia here. we're a building a halal database, still under development & testing phase. I humbly request your permission to use your code as a reference to implement prayertime query to our website @ www.ishalal.com, by time we go live i'll credit you properly. Thsnk you.
ReplyDeleteو عليكم السلام و رحمة الله و بركاته
DeletePlease do. And good luck with your project.
Thank you Mr. Mahmoud, here is a semidirect translation of your code in Golang, but the result is not correct and i'm not familiar with algorithm in used. It would be great to hear your advice on this.
Deletehttps://gist.github.com/2917151
Assalamualaikum, Mahmoud bhai can you tell me the formula to get midnight that applies on this algorith to this algorith plz i am in realy need of this.looking forward to your possitive response.thankyou
ReplyDeleteWell, I don't understand the question. Isn't midnight always at 12:00am (or 00:00)?
Deletemidnight means ending time of isha namaz.it is different according to different mathhabs i.e(hanafi,shafi,hanbli,jafri....).calculation formulas are given in this link(http://praytimes.org/calculation#Implementation )for example according to shafi isha ends at(sunrisesunset)/2.but when i aplly this formula to your code i gets wrong answer.scince you have shortened the algorithm.can you tell how this formula apply to your algo..plz help me out.thanxz alot
ReplyDeleteIf this is the case, then sunrise is "sunRiseTime" in the code and sunset is "maghribTime" in the code.
DeleteSo it would be (sunRiseTimemaghribTime)/2 then use doubleToHrMin to get the time in Hour and Minute.
but applying this formula i am not getting the correct result.
ReplyDeletethere???
ReplyDeleteNeeding help?
Deletethese formulas are wrong, i have to calculate asr shaafi and hanafi and my sir had given me this formula whch i hav converted in c++ format, still its giving wrong calcution, need ur help asap.. the values in constructor are of lahore pakistan
Deleteclass Asar_Hanafi:public Maghrib
{
public:
Asar_Hanafi(double l, double lt, double t, double la, double d):Maghrib(l,lt,t,la,d)
{
localtime= lt;
longitude=l;
twilight=t;
lattitude=la;
declination=d;
}
double getA()
{
double a,b,c,d;
b=lattitudedeclination;
c=(2+tan(b*PI/180));
d=atan(c)*PI/180;
cout<<d<<endl;
return d;
}
double getA_HH(double d)
{
double l, b, A_HH,c,f,e;
l=sin(d*(PI/180));
b=(sin(lattitude*PI/180)*sin(declination*PI/180));
e=(lb);
c=(cos(lattitude*PI/180)*cos(declination*PI/180));
f=e/c;
A_HH=acos(d)*180.0/PI;
return A_HH;
}
double getZA_H()
{
double a, b, c, d;
a=((longitudelocaltime)/15);
b= 3.7/60;
c= 12+a+b;
return c;
}
void getA_H(double A_HH, double c)
{
double l,m,q;
l=A_HH/15;
m=c+l;
double t= int(m);
double w=((mt)*60);
q=int (w);
cout<<t<<"hour"<<q<<"min"<<endl;
}
};
class Asar_Shafi:public Maghrib
{
public:
Asar_Shafi(double l, double lt, double t, double la, double d):Maghrib(l,lt,t,la,d)
{
localtime= lt;
longitude=l;
twilight=t;
lattitude=la;
declination=d;
}
double getA()
{
double a,b,c,d;
b=lattitudedeclination;
c=(1+tan(b*PI/180));
cout<<c<<endl;
// in d cot inverse should be taken bt ye prob krha hai, and same prob arhi hai asr SHAFI mein bhi..
d=atan(c)*PI/180;
//cout<<a<<endl;
return d;
}
double getA_SH(double d)
{
double l, b, A_HH,c,f,e;
l=sin(d*(PI/180));
b=(sin(lattitude*PI/180)*sin(declination*PI/180));
e=(lb);
c=(cos(lattitude*PI/180)*cos(declination*PI/180));
f=e/c;
A_HH=acos(d)*180.0/PI;
return A_HH;
}
double getZA_S()
{
double a, b, c, d;
a=((longitudelocaltime)/15);
b= 3.7/60;
c= 12+a+b;
return c;
}
void getA_S(double A_HH, double c)
{
double l,m,q;
l=A_HH/15;
m=c+l;
double t= int(m);
double w=((mt)*60);
q=int (w);
cout<<t<<"hour"<<q<<"min"<<endl;
}
Salam Bro,
ReplyDeleteWould you be able to kindly explain how to get
Fajr Twilight:
Esha Twilight:
I searched in google and could not find anything.
I did not calculate them, but got them as constants. I searched for values for my city: Cairo.
DeleteSalam brother Mahmoud, thank you very much for the code. The code run asis on Arduino sketch.
ReplyDeleteWa Alaykom Alsalam,
DeleteGlad to hear that. C++ is great (actually, C is greater) :D
Assalamualaikum brother Mahmoud..I am a beginner in C programming language.I need your help. How to add the Imsyak time that is 10 minutes before fajr time in the listing program above?
ReplyDeleteWaalaykom Assalam,
DeleteYou can subtract hours from the return values before converting them to hourMinute. So in case of minutes, you subtract a fraction of an hour. Like this (note the .0 to make sure a float is returned):
imsaak = fajr  (10/60.0);
then do the conversion like this:
int hours, minutes;
doubleToHrMin(imsaak, hours, minutes);
I 've added the imsyak time to the list of program..it's working!
DeleteThank you very..very..very much my brother..wassalam.
Assalamualaikum , thanks for your explanation about prayer times calculation. i use your calculation for my project and its work great. its working.
ReplyDeleteI use microcontroller and two different display to display prayer time. ther first i use seven segment and then i try to use LCD display with mp3 player to play adzan automaticaly. thank you very much.
Walaykom Assalam,
DeleteThank you so much for your comment. It encourages me to keep sharing to see beautiful output like yours.
Can you pls send me your email Duwi Arsana
DeleteAssalamu alaykum brother Mahmoud,
ReplyDeleteThank you for the code, i can run it smoothly. For Fajr, Sunrise, Zuhr, Maghrib and Isya the time later around 14 minutes than standard prayer time. But for Asr the result different from standard prayer time. In my place in Jakarta, Asr should be on 15:13 but the result from above code 13:33.
Could you mind give clue, why that happen and what correction should i implemented in code.
Jazaka Allaho khayran
Walaykom Assalam,
DeleteHow about trying to change the last two numbers in the function call (fajrTwilight and ishaTwilight)?
I gave a table of some organizations and their used degrees. So maybe you can look for the approved organization in Pakistan (the first row in the table I gave has Pakistan) and try with it.
Jazaka Allahu khayran brother.
جزاك الله عنا وعن الامة خيرا
ReplyDeleteAssalamu'alaikum,
ReplyDeleteBrother, you really did a good job with this algortithm; I myself have no idea how to get all the formulas. I managed to port it to C#; works like a charm  especially with the Egyptian calculation one. For sure I will put you in credit when I use this algorithm in my project.
Keep sharing good things, bro.. and jazaakallaahu khairan..
I'm glad I could help. Thank you for your comment.
DeleteAssalamu'alaiku akhii.
ReplyDeleteIt is great tutorial. Thanks for your explaination about prayer times calculation.
I use your calculation with C Code blocks and I found trouble with ashar time. My location is 112.217E, 7.533S (7.533) East Java Indonesia.
I use your calculation for my project to with AVR
thanks a lot
وعليكم السلام ورحمة الله وبركاته
DeleteSo the Isha prayer time is not exactly as it should be for your location?
isya' time is ok but ashar time is not exactly
DeleteI don't know what to say. I used alreadywritten mathematical equations to write this code, but I don't know much about changing the equation itself.
DeleteI have ported this to C# and Java; both give correct result. Of course you can't compare down to minutes with your local adzan call. Maybe try with different twilight/angle.
DeleteGooooood jobb
ReplyDeletethank you for your program, in Algeria constants:
Fajr Twilight: 19.5
Esha Twilight: 17.5
remain unchanged as cairo?
Hello Far Zeha,
DeleteI'm glad I could help :)
The angles depend on the organization you follow in your country for prayer calculations. I use "Egyptian General Authority of Survey" values for Cairo and "Muslim World League" values for Berlin.
thank you for the answer.
ReplyDeleteI have another question:
I want to add a constant offset after calculating time of prayer.
how to do it ?
example:
Fajr: 5:24 + 10 ==> 5:34
You can add/subtract hours from the return values before converting them to hourMinute. So in case of minutes, you add a fraction of an hour. Like this (note the .0 to make sure a float is returned):
Deletenew_fajr = fajr + (10/60.0);
then do the conversion like this:
int hours, minutes;
doubleToHrMin(new_fajr, hours, minutes);
شكرا جزيلا و جزاك الله كل خير
ReplyDeleteجزانا وإياكم
Deletei try to use the calculation into my arduino, but i have problem with this code
ReplyDeleteint main() {
double fajr, sunRise, zuhr, asr, maghrib, isha;
calcPrayerTimes(2012,1,18, 30.2, 30, 2, 19.5, 17.5,
fajr, sunRise, zuhr, asr, maghrib, isha);
int hours, minutes;
doubleToHrMin(fajr, hours, minutes);
std::cout << "Fajr: " << hours << ":" << minutes << std::endl;
doubleToHrMin(sunRise, hours, minutes);
std::cout << "Sunrise: " << hours << ":" << minutes << std::endl;
doubleToHrMin(zuhr, hours, minutes);
std::cout << "Zuhr: " << hours << ":" << minutes << std::endl;
doubleToHrMin(asr, hours, minutes);
std::cout << "Asr: " << hours << ":" << minutes << std::endl;
doubleToHrMin(maghrib, hours, minutes);
std::cout << "Maghrib: " << hours << ":" << minutes << std::endl;
doubleToHrMin(isha, hours, minutes);
std::cout << "Isha: " << hours << ":" << minutes << std::endl;
}
need help
You did not mention the problem :)
Delete"std::cout << "Maghrib: " << hours << ":" << minutes << std::endl;" will not run in arduino.
Deletereplace these from.....
doubleToHrMin(fajr, hours, minutes);
Serial.print("Fajr ");
Serial.print(hours);
Serial.print(":");
Serial.println(minutes);
could you plz send me your email Mahmoud Adly Ezzat
ReplyDeleteالسلام علیکم
ReplyDeletei just wanted to know if you give us permisson to use your code !
we want to make clock for masque
وعليكم السلام ورحمة الله وبركاته
DeleteYes, sure! Go ahead.
thanks
Deletei saw something in your code that i cant figure out !
you used "int timeZone" so what will happen in case that timezone is 3.5 it will saved to int timezone as 3 ! is it correct ?
Yes, right.
DeleteI haven't used similar timezones before, so I did not put that in mind. =)
many thanks in advance
ReplyDeletehow can i get table of cities, Country, longitude, latitude and time Zone
For all the cities, you can find databases and lists online.
DeleteAssalamualaikum brother,
ReplyDeleteCould you give example to calculate praying time for Indonesia Region.
Thanks for your kindness,
Dedy Yasriady
Wa'alaykom Assalam,
DeleteI have an example at the end of the post. Or here is the full example in one file https://ideone.com/sqNLrg
The passed parameter will depend on your country. So for example, Jakarta should have somthing like this:
Date: 1522017
Longitude: 106.8227
Latitude: 6.1745
Time Zone: +7
Fajr Twilight: 19.5 (depends on the approved calculation method in your country)
Esha Twilight: 17.5 (depends on the approved calculation method in your country)
This comment has been removed by the author.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteAssalamu'alaikum my brother Mahmoud Adly Ezzat.
ReplyDeleteThank you for the code, this is very usefull.
I'm from Indonesia. I think there's something you need to change about Asr time. Because when I set the location in Indonesia(with long : 112.75, lat :7.492, and timeZone : 7), the Asr time wouldn't work correctly. In line 102 from ideone.com :
double Asr_Alt = radToDeg(atan(1 + tan(degToRad(latitude  Dec))));
it should be like this :
double Asr_Alt = radToDeg(atan(1 + tan(degToRad(abs(latitude  Dec)))));
The reason is, because not every place's latitude is positive value, while from many reference website I've search, the value inside tan should be positive. Hope this can help others. Thank you.
:)
Best Regards,
Reza
وعليكم السلام ورحمة الله وبركاته :)
DeleteThanks A LOT for this note.
thanks you so much this is the best
ReplyDeleteThanks a lot. Glad I could help =)
Delete