"Impossible" Prayer Times?
 

The phenomenon of Persistent twilight

Very Late and Very Early Fajr Times!!!

Examine the table below. You will notice that Isha time becomes very late and fajr time comes very early, till the difference between them is less than an hour!

You will note that in some summer months Isha prayer times are given for times greater than 24hrs e.g. 2005 May 18th the time given is 24:43 . This means that the prayer time is actually 00:43 on 2005 May 19th!

Obviously, it is very difficult to perform the Isha and fajr prayers or to fast and perform taraweeh prayer in Ramadan.

No Isha times in some summer months

But, you will also note that for some summer months there are no times given for start of twilight or end of twilight. This phenomena is called persistent twilight.

At Northerly Latitudes (beyond 48 e.g. Britain) the features that legally define the true Fajr and Isha during the summer months ( ~25th May to 18th July) seem to be absent. This phenomena is called persistent twilight as you can see in the table below. So, how does one also fast during these months?

You will also note that some twilights do not occur during the summer months. This is because the Sun does not get far enough below the horizon for the twilight to occur. The times given below are unadjusted prayer times when the altitude of the Sun is 17.5 degrees.


 
Twilight Times of Twilights when the altitude of the Sun is 17.5 degrees.
Shadow 1 Times when the length of the shadow cast by a vertical stick is equal to its length plus length of its shadow at transit. This is the Shaafi, Hambali and Maliki Asr time.
Shadow 2 Times when the length of the shadow cast by a vertical stick is equal to twice its length plus length of its shadow at transit. This is the Hanafi Asr time.
Transit Time of Meridian passage of Sun. The time for noon prayer (Dhuhr) begins after midday

NOTE: These are unadjusted prayer times.
 

Month Day Twilight Sunrise Transit Shadow 1 Shadow 2 Sunset
Twilight

 
2005 MAY 16 01:57 05:03 12:56 17:10 18:19 20:49 00:01
2005 MAY 17 01:51 05:02 12:56 17:11 18:20 20:51 00:07
2005 MAY 18 01:44 05:00 12:56 17:11 18:21 20:53 00:15
2005 MAY 19 01:37 04:59 12:56 17:12 18:22 20:54 00:23
2005 MAY 20 01:28 04:58 12:56 17:12 18:23 20:55 00:35
2005 MAY 21 01:16 04:58 12:56 17:13 18:24 20:57 **:**
2005 MAY 22 **:** 04:55 12:56 17:14 18:24 20:58 **:**
2005 MAY 23 **:** 04:54 12:56 17:14 18:25 21:00 **:**
2005 MAY 24 **:** 04:52 12:56 17:15 18:26 21:01 **:**
2005 MAY 25 **:** 04:51 12:56 17:15 18:27 21:02 **:**
2005 MAY 26 **:** 04:50 12:57 17:16 18:28 21:04 **:**
2005 MAY 27 **:** 04:49 12:57 17:16 18:28 21:05 **:**
2005 MAY 28 **:** 04:48 12:57 17:17 18:29 21:06 **:**
2005 MAY 29 **:** 04:47 12:57 17:17 18:30 21:07 **:**
2005 MAY 30 **:** 04:46 12:57 17:18 18:30 21:09 **:**
2005 MAY 31 **:** 04:45 12:57 17:18 18:31 21:10 **:**
 
Month Day Twilight:
Fajr
Sunrise Transit Shadow 1 Shadow 2 Sunset
Twilight:

Isha
 
2005 JUNE 1 **:** 04:44 12:57 17:19 18:32 21:11 **:**
2005 JUNE 2 **:** 04:44 12:57 17:19 18:33 21:12 **:**
2005 JUNE 3 **:** 04:43 12:58 17:20 18:33 21:13 **:**
2005 JUNE 4 **:** 04:42 12:58 17:20 18:34 21:14 **:**
2005 JUNE 5 **:** 04:41 12:58 17:21 18:34 21:15 **:**
2005 JUNE 6 **:** 04:41 12:58 17:21 18:35 21:16 **:**
2005 JUNE 7 **:** 04:40 12:58 17:21 18:36 21:17 **:**
2005 JUNE 8 **:** 04:40 12:59 17:22 18:36 21:18 **:**
2005 JUNE 9 **:** 04:39 12:59 17:22 18:37 21:19 **:**
2005 JUNE 10 **:** 04:39 12:59 17:23 18:37 21:19 **:**
2005 JUNE 11 **:** 04:39 12:59 17:23 18:38 21:20 **:**
2005 JUNE 12 **:** 04:38 12:59 17:23 18:38 21:21 **:**
2005 JUNE 13 **:** 04:38 13:00 17:24 18:38 21:21 **:**
2005 JUNE 14 **:** 04:38 13:00 17:24 18:39 21:22 **:**
2005 JUNE 15 **:** 04:38 13:00 17:24 18:39 21:22 **:**
2005 JUNE 16 **:** 04:38 13:00 17:25 18:39 21:23 **:**
2005 JUNE 17 **:** 04:38 13:00 17:25 18:40 21:23 **:**
2005 JUNE 18 **:** 04:38 13:01 17:25 18:40 21:24 **:**
2005 JUNE 19 **:** 04:38 13:01 17:25 18:40 21:24 **:**
2005 JUNE 20 **:** 04:38 13:01 17:26 18:41 21:24 **:**
2005 JUNE 21 **:** 04:38 13:01 17:26 18:41 21:25 **:**
2005 JUNE 22 **:** 04:38 13:02 17:26 18:41 21:25 **:**
2005 JUNE 23 **:** 04:39 13:02 17:26 18:41 21:25 **:**
2005 JUNE 24 **:** 04:39 13:02 17:26 18:41 21:25 **:**
2005 JUNE 25 **:** 04:39 13:02 17:26 18:41 21:25 **:**
2005 JUNE 26 **:** 04:40 13:02 17:27 18:41 21:25 **:**
2005 JUNE 27 **:** 04:40 13:03 17:27 18:42 21:25 **:**
2005 JUNE 28 **:** 04:41 13:03 17:27 18:42 21:25 **:**
2005 JUNE 29 **:** 04:41 13:03 17:27 18:42 21:24 **:**
2005 JUNE 30 **:** 04:42 13:03 17:27 18:42 21:24 **:**
Month Day Twilight:
Fajr
Sunrise Transit Shadow 1 Shadow 2 Sunset
Twilight:

Isha
 
2005 JULY 1 **:** 04:43 13:03 17:27 18:41 21:24 **:**
2005 JULY 2 **:** 04:43 13:04 17:27 18:41 21:23 **:**
2005 JULY 3 **:** 04:44 13:04 17:27 18:41 21:23 **:**
2005 JULY 4 **:** 04:45 13:04 17:27 18:41 21:22 **:**
2005 JULY 5 **:** 04:46 13:04 17:27 18:41 21:22 **:**
2005 JULY 6 **:** 04:47 13:04 17:27 18:41 21:21 **:**
2005 JULY 7 **:** 04:48 13:04 17:27 18:40 21:21 **:**
2005 JULY 8 **:** 04:49 13:05 17:27 18:40 21:20 **:**
2005 JULY 9 **:** 04:50 13:05 17:26 18:40 21:19 **:**
2005 JULY 10 **:** 04:51 13:05 17:26 18:39 21:18 **:**
2005 JULY 11 **:** 04:52 13:05 17:26 18:39 21:18 **:**
2005 JULY 12 **:** 04:53 13:05 17:26 18:39 21:17 **:**
2005 JULY 13 **:** 04:54 13:05 17:26 18:38 21:16 **:**
2005 JULY 14 **:** 04:55 13:05 17:25 18:38 21:15 **:**
2005 JULY 15 **:** 04:56 13:05 17:25 18:37 21:14 **:**
2005 JULY 16 **:** 04:58 13:06 17:25 18:37 21:13 **:**
2005 JULY 17 **:** 04:59 13:06 17:24 18:36 21:12 **:**
2005 JULY 18 **:** 05:00 13:06 17:24 18:35 21:10 **:**
2005 JULY 19 **:** 05:02 13:06 17:24 18:35 21:09 **:**
2005 JULY 20 **:** 05:03 13:06 17:23 18:34 21:08 **:**
2005 JULY 21 **:** 05:04 13:06 17:23 18:33 21:07 01:04
2005 JULY 22 01:09 05:06 13:06 17:22 18:33 21:05 00:41
2005 JULY 23 01:31 05:07 13:06 17:22 18:32 21:04 00:31

’... reproduced, with permission, from data supplied by HM Nautical Almanac Office, Copyright Council for the Central Laboratory for the Research Councils’.

One of the projects the Cambridge Prayer Times Team wish to collaborate on is the observation and recording of the times of the true dawn (subh Sadiq) and Isha insha Allah.