Math w/o Calculator :
Here's a method for calculating all prayer times w/o a calculator and for any city. You need to use the chart bellow for equation of time and sun's altitude. The two values in the chart varies for date but not for place.
And for any city you need to know these two things.
- Base time for sunrise, sunset, subh, esa, noon.
The above two varies for place, but not for date.
Next, calculation method for Dhaka, as an example :
Base sunrise 5:55, sunset 6:02, Multiplier is 1.8.
From these we can figure out Sunrise and sunset for example today Dec-10th.
Equation of time on Dec-10th : -7 mins.
Sun's altitude : -23 degrees.
Sun rise = Base Time + Eq of Time - Alt * Multiplier.
Sun set = Base Time + Eq of Time + Alt * Multiplier.
Thus,
Sun rise today is : 5:55 - 7 mins + 23*1.8 mins = 6:29. Which actually is at 6:30. 1 min diff.
And sun set 6:01 - 7 mins - 23*1.8 mins = 5:13, where actual is 5:12, giving once again 1 min difference.
The chart follows. But you don't need to memorize all these numbers. Altitude value is a sinusoidal wave. And equation of time, though can be calculated, can be approximately memorized from a poem I shared previously. More on these later, inshaAllah.
Date, Eq_Time, Altitude
Jan-01, 3, -23
Jan-02, 4, -23
Jan-04, 5, -23
Jan-06, 6, -22
Jan-08, 7, -22
Jan-11, 8, -22
Jan-13, 9, -21
Jan-16, 10, -21
Jan-19, 11, -20
Jan-23, 12, -19
Jan-27, 13, -18
Jan-31, 13, -17
Feb-02, 14, -17
Feb-04, 14, -16
Feb-07, 14, -15
Feb-10, 14, -14
Feb-13, 14, -13
Feb-16, 14, -12
Feb-19, 14, -11
Feb-22, 13, -10
Feb-24, 13, -9
Feb-27, 13, -8
Mar-01, 12, -8
Mar-02, 12, -7
Mar-04, 12, -6
Mar-05, 11, -6
Mar-07, 11, -5
Mar-09, 11, -4
Mar-10, 10, -4
Mar-12, 10, -3
Mar-13, 9, -3
Mar-15, 9, -2
Mar-17, 8, -1
Mar-20, 8, 0
Mar-21, 7, 0
Mar-22, 7, 1
Mar-24, 6, 1
Mar-25, 6, 2
Mar-27, 5, 3
Mar-30, 5, 4
Mar-31, 4, 4
Apr-01, 4, 5
Apr-03, 3, 5
Apr-04, 3, 6
Apr-06, 2, 6
Apr-07, 2, 7
Apr-09, 2, 8
Apr-10, 1, 8
Apr-12, 1, 9
Apr-14, 0, 9
Apr-15, 0, 10
Apr-18, -1, 11
Apr-20, -1, 12
Apr-23, -2, 13
Apr-26, -2, 14
Apr-28, -3, 14
Apr-30, -3, 15
May-03, -3, 16
May-06, -3, 17
May-08, -4, 17
May-10, -4, 18
May-14, -4, 19
May-18, -4, 20
May-21, -3, 20
May-23, -3, 21
May-29, -3, 22
May-31, -2, 22
Jun-05, -2, 23
Jun-06, -1, 23
Jun-11, 0, 23
Jun-16, 1, 23
Jun-21, 2, 23
Jun-25, 3, 23
Jun-30, 4, 23
Jul-05, 5, 23
Jul-08, 5, 22
Jul-12, 6, 22
Jul-16, 6, 21
Jul-21, 6, 20
Jul-25, 7, 20
Jul-26, 7, 19
Jul-28, 6, 19
Jul-31, 6, 18
Aug-03, 6, 17
Aug-07, 6, 16
Aug-10, 5, 16
Aug-11, 5, 15
Aug-14, 5, 14
Aug-16, 4, 14
Aug-17, 4, 13
Aug-20, 3, 12
Aug-23, 3, 11
Aug-24, 2, 11
Aug-26, 2, 10
Aug-28, 1, 10
Aug-29, 1, 9
Aug-31, 0, 9
Sep-01, 0, 8
Sep-03, -1, 8
Sep-04, -1, 7
Sep-06, -2, 6
Sep-09, -3, 5
Sep-12, -4, 4
Sep-14, -4, 3
Sep-15, -5, 3
Sep-17, -5, 2
Sep-18, -6, 2
Sep-19, -6, 1
Sep-20, -7, 1
Sep-22, -7, 0
Sep-23, -8, 0
Sep-25, -8, -1
Sep-26, -9, -1
Sep-27, -9, -2
Sep-29, -10, -2
Sep-30, -10, -3
Oct-02, -11, -4
Oct-05, -12, -5
Oct-07, -12, -6
Oct-09, -13, -6
Oct-10, -13, -7
Oct-13, -14, -8
Oct-15, -14, -9
Oct-17, -15, -9
Oct-18, -15, -10
Oct-21, -15, -11
Oct-22, -16, -11
Oct-24, -16, -12
Oct-27, -16, -13
Oct-30, -16, -14
Nov-02, -16, -15
Nov-05, -16, -16
Nov-08, -16, -17
Nov-12, -16, -18
Nov-15, -15, -18
Nov-16, -15, -19
Nov-20, -14, -20
Nov-24, -13, -21
Nov-28, -12, -21
Nov-30, -11, -22
Dec-03, -10, -22
Dec-06, -9, -22
Dec-07, -9, -23
Dec-08, -8, -23
Dec-10, -7, -23
Dec-12, -6, -23
Dec-15, -5, -23
Dec-17, -4, -23
Dec-19, -3, -23
Dec-21, -2, -23
Dec-23, -1, -23
Dec-25, 0, -23
Dec-27, 1, -23
Dec-29, 2, -23
Dec-31, 3, -23