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<h1 id="page-title"><div id="g_title"><h2 style="text-align: center;"><font size="6">The Determination <br>of Salaat Times</font></h2></div></h1>
<div style="clear: both;"></div>
<p class="description"></p><div id="g_description"><p style="text-align: right;"><strong><font size="2">by Dr. Monzur Ahmed</font></strong></p>
<p style="text-align: right;"><font size="1">minor updates by Dr. Ayad Abdulmawla <br></font></p></div>
<div style="clear: both;"></div>
</div>
</div>
<!-- /editable --><!-- /wrapper --><!-- /header -->
<div id="main-content">
<div class="wrapper">
<div class="content-item"><div id="g_body"><h2> </h2>
<h2>1. Introduction</h2>
<p>The five Islamic prayers are named Fajr, Zuhr, Asr, Maghrib and
Isha. The timing of these five prayers varies from place to place and
from day to day. It is obligatory for Muslims to perform these prayers
at the correct time. </p>
<p>The prayer times for any given location on earth may be determined
mathematically if the latitude and longitude of the location are known.
However, the theoretical determination of prayer times is a lengthy
process. Much of this tedium may be alleviated by using computer
programs. </p>
<p></p><a href="" name="2. Definition"></a>
<h2> </h2>
<h2>2. Definition of prayer times</h2>
<p></p>
<ul>
<li>FAJR starts with the dawn or morning twilight. Fajr ends just before sunrise. </li></ul>
<p></p>
<ul>
<li>ZUHR begins after midday when the trailing limb of the sun has
passed the meridian. For convenience, many published prayer timetables
add five minutes to mid-day (zawal) to obtain the start of Zuhr. Zuhr
ends at the start of Asr time. </li></ul>
<p></p>
<ul>
<li>The timing of ASR depends on the length of the shadow cast by an
object. According to the Shafi school of jurisprudence, Asr begins when
the length of the shadow of an object exceeds the length of the object.
According to the Hanafi school of jurisprudence, Asr begins when the
length of the shadow exceeds TWICE the length of the object. In both
cases, the minimum length of shadow (which occurs when the sun passes
the meridian) is subtracted from the length of the shadow before
comparing it with the length of the object. </li></ul>
<p></p>
<ul>
<li>MAGHRIB begins at sunset and ends at the start of isha. </li></ul>
<p></p>
<ul>
<li>ISHA starts after dusk when the evening twilight disappears. </li></ul>
<center><img tabindex="0" src="salaattimes_files/solarcy.gif"></center>
<p></p>
<table colspec="L20 L20 L20" border="1" cellpadding="3" cellspacing="1">
<caption align="top">
<h3>Salat Times</h3></caption>
<tbody>
<tr>
<th> </th>
<th>Start</th>
<th>End</th></tr>
<tr>
<th>Fajr</th>
<td>When whitishness begins to appear on the horizon (dawn)</td>
<td>At beginning of sunrise</td></tr>
<tr>
<th>Zuhr</th>
<td>After sun's trailing limb crosses meridian</td>
<td>Start of Asr</td></tr>
<tr>
<th>Asr</th>
<td>When length of shadow =2x length of object + noon shadow (Hanafi) or <br>When length of shadow = length of object + noon shadow (Shafi)</td>
<td>Before sunset</td></tr>
<tr>
<th>Maghrib</th>
<td>Sunset</td>
<td>Reddishness in the sky</td></tr>
<tr>
<th>Isha</th>
<td>After reddishness in sky (dusk) ends</td>
<td>Midnight (afzal), next fajr (makruh)</td></tr></tbody></table>
<center> </center>
<p> </p>
<p><a href="" name="3.Twilight"></a></p>
<h2> </h2>
<h2>3. What is twilight?</h2>
<p>If the earth did not have an atmosphere, the sky would become dark
immediately after sunset. The earth's atmosphere causes scattering of
sunlight so that light reaches the observer <strong>before</strong> sunrise and <strong>after</strong>
sunset. This scattered light is called twilight. After sunset, as the
depression of the sun increases the sky gets darker and darker until no
scattered light reaches the observer. Conversely, in the morning light
starts to appear in the sky even before sunrise. The morning twilight
is called dawn whilst the evening twilight is known as dusk. </p>
<p></p>
<center><img tabindex="0" src="salaattimes_files/depr.gif"></center>
<p>In astronomy the twilight period is divided into civil, nautical and
astronomical twilight corresponding to solar depressions of 6, 12 and
18 degrees respectively. </p>
<p></p>
<center><img tabindex="0" src="salaattimes_files/twilgrph.gif"></center>
<p></p>
<ul>
<li>Civil twilight - roughly equivalent to lighting up time. The
brightest stars are visible and at sea the horizon is clearly visible. </li></ul>
<ul>
<li>Nautical twilight - the horizon at sea ceases to be clearly visible
and it is impossible to determine altitudes with reference to the
horizon. </li></ul>
<ul>
<li>Astronomical twilight- when it is truly dark and no perceptible twilight remains. </li></ul>
<p></p><a href="" name="4. Twilight and calc"></a>
<h2> </h2>
<h2>4. Twilight and calculation of fajr and isha</h2>
<p>Fajr starts with the morning twilight (dawn) whilst isha starts at
the end of the evening twilight (dusk). There is some debate as to
which twilight angle should be used in the calculation of fajr/isha.
For a discussion on the subject, I refer you to Dr. Ilyas' book:
Astronomy of Islamic Times for the Twenty- first Century. Here is a
brief extract from chapter five of Dr. Ilyas' book (in italics): </p>
<p><em>" In modern times, astronomical twilight (18 degrees) has come
to be widely used for the determination of isha and fajr times. As the
average intensity curve of evening twilight indicates, the flux
decreases to a minimum level, and thus it would seem appropriate that
even for Islamic purposes, this should indicate a reasonable starting
value for the end of 'astro-lslamic twilight' (AIT). Indeed, 18 degrees
depression was a commonly used value for fajr and isha in the medieval
period, when it must have been based on careful observations.
Nevertheless, slight variations from this value- between 16 degrees and
20 degrees- were also used during the medieval period. According to
King, 20 degrees and 16 degrees were the parameters used by Ibn Yunus
for morning and evening AIT respectively, whereas 19 degrees and 17
degrees were the parameters used by various Egyptian astronomers. Nasr
also refers to 19 degrees being used in the Islamic world for the fajr
and isha times. King has confirmed that although Muslim astronomers
widely used 18 degrees/l8 degrees symmetrical values or a slight
variation to 19 degrees/17 degrees (morning/evening)-and in a few
(earlier) cases even 20 degrees/16 degrees values were adopted-no
record has been found of the use of a value as small as 15 degrees.
This is of specific interest to us because a few years ago, values of
15 degrees/15 degrees for both AlTs were proposed by Bagvi on the
authority of Maulana Rashid Ahmad Ludianvi of Karachi, who is reported
to have made some observations personally. Indeed, I myself followed
Bagvi in preparing the first South Australian Islamic Time Table,
although I did consider the need to examine the matter very carefully
and introduced a distinct term for it. Subsequently, this 15 degrees
proposition has come under criticism and is apparently not proved by
others' observations made in recent years in that particular area
(Karachi). Concern on this matter is obviously understandable, because
an erroneous delay in the beginning of fajr would have serious
implications for the beginning of the Fast. One of the useful studies
arguing against this 15 degrees depression for AIT is that of Latiff,
who claims to have conducted some observational work. Unfortunately,
Latiff has argued for a fixed 18 degrees/18 degrees case for all over
the globe-no less and no more. This, it seems, may not be the true
situation either as there seems to be some room for geographical
variability and perhaps 18 degrees serves as a good upper limit only.
The value for morning AIT has widely been used as 18 degrees, although
a practice of using 20 degrees prevails in Egypt and Indonesia/Malaysia
(under Egyptian influence, apparently owing to the concerned persons
having been trained there). Possibly, 20 degrees is taken as a
safeguard because of the sanctification of the Fast. On the other hand,
the use of smaller values than 18 degrees for India and Yemen has been
reported to me in personal communications by Abdul Hafiz Maniar of
Surat, India, and Dr. M.M. Qurashi of Islamabad, Pakistan,
respectively. However, as we have noted elsewhere, in general, at 18
degrees depression, no detectable trace of twilight flux will be found,
meaning that 18 degrees represents an upper limit. "</em></p>
<p>Generally, using smaller twilight angles will produce later fajr times and earlier isha times. </p>
<p>eg for<strong> London</strong> (51:32N, 00:06W, Time zone 0 ),<br>On 1st January 1996: </p><pre> Fajr Isha<br>18 degrees 6:02 18:04<br>15 degrees 6:22 17:43<br></pre>
<p>The two graphs below show the change in the timing of the prayer
times during the year is shown for London below: (F= Fajr, Z=Zuhr,
A2=Hanafi Asr, M=Maghrib, I=Isha). </p>
<p>In the first graph (below), 15 degrees has been used for calculation of both Fajr and Isha. </p>
<p></p>
<center><img tabindex="0" src="salaattimes_files/twil15.gif"></center>
<p></p>
<center>
<h5>Diagram produced by Prayer Time Calculator</h5><br></center>In the
second graph (below), 18 degrees has been used for calculation of Fajr
and Isha. Note that in the second example, Fajr starts earlier and Isha
starts later. <p></p>
<center><img tabindex="0" src="salaattimes_files/twil18.gif"></center>
<p></p>
<center>
<h5>Diagram produced by Prayer Time Calculator</h5></center>
<hr>
<p><a href="" name="5. Conventions"></a></p>
<h2> </h2>
<h2>5. Conventions currently in use</h2>Several conventions for the
calculation of Fajr and Isha are already in use in various countries.
Fajr and Isha times are usually calculated using fixed twilight angles
as discussed above but some countries also use a method involving
adding/subtracting a fixed interval of time to sunset/sunrise
respectively . Using the latter method, a time interval is subtracted
from sunrise to obtain Fajr whilst the interval is added to sunset to
obtain Isha. The methods used by some Islamic organisations are are
summarised in the following table: <p></p>
<table colspec="L20 L20 L20 L20 L20" border="1">
<tbody>
<tr>
<th>Organisation</th>
<th>Fajr - twilight angle</th>
<th>Isha - twilight angle</th>
<th>Region</th>
<th><br></th></tr>
<tr>
<td>University of Islamic Sciences, Karachi</td>
<td>18</td>
<td>18</td>
<td>Pakistan, Bangladesh, India, Afganistan, parts of Europe</td>
<td><br></td></tr>
<tr>
<td>Islamic Society of North America (ISNA)</td>
<td>15</td>
<td>15</td>
<td>Parts of USA & Canada, parts of UK</td>
<td><br></td></tr>
<tr>
<td>World Islamic League</td>
<td>18</td>
<td>17</td>
<td>Europe, Far East, parts of USA</td>
<td><br></td></tr>
<tr>
<td>Um Ul-Qura, Makkah</td>
<td>19</td>
<td>90 mins after Maghrib, 120 mins during Ramadhan</td>
<td>Arabian Peninsula</td>
<td><br></td></tr>
<tr>
<td>Egyptian General Organisation of Surveying</td>
<td>19.5</td>
<td>17.5</td>
<td>Africa, Syria, Iraq, Lebanon, Malaysia, parts of USA</td>
<td><br></td></tr></tbody></table>
<p></p>
<center> </center>
<h2> </h2>
<h2>6. Persisting Twilight </h2>
<p>At extreme latitudes the twilight may persist between sunset and the
next sunrise for certain months of the year. In these months the sun
does not go below the horizon by a sufficient amount to abolish
twilight. Hence there is no true night. Under these circumstances, Fajr
and Isha times may be calculated using one of four agreed principles
(refs 4 & 2): </p>
<p><strong>1. Nearest latitude</strong><em>(Aqrab Al-Balad)</em> - add
the interval between sunset and isha for a location on latitude 48
degrees to the local sunset time to obtain time for local isha.
Similarly the interval between fajr and sunrise for a location on
latitude 48 degrees is subtracted from local sunrise to obtain local
fajr time. </p>
<p><strong>2. Nearest day </strong><em>(Aqrab Al-Ayyam)</em> - use fajr and isha times from the last day when it was possible to calculate these times in the normal way for that location. </p>
<p><strong>3. Middle of night</strong><em>(Nisf Al-Lail)</em> - split
interval between sunrise and sunset into two halves. Isha is offered
before the midpoint (e.g. 15 minutes before) and fajr is offered after
the midpoint. </p>
<p><strong>4. One seventh of night</strong><em>(Sube Al-Lail)</em> -
split interval between sunset and sunrise into seven segments. Isha is
offered after the first segment and fajr is offered after the sixth
segment. </p>
<h2> </h2>
<h2>7. Calculation of Salat Times - technical notes</h2>To calculate
the prayer times for a certain place we need to know the latitude (B)
and longitude (L) of the location and its reference longitude (R). B
and L may be obtained from an atlas and R may be calculated by
multiplying 15 by the difference between local time and GMT (i.e. 15 x
Time Band). <p>We also need to know two astronomical measures called the
declination angle of the sun (D) and the real time-mean time
difference, also known as the equation of time (T). </p>
<p>Declination is the angular distance between a celestial object and
the celestial equator. The Declination and the Right Ascension are used
together to give the position of a star with reference to the celestial
equator and the vernal equinox respectively. </p>
<p>The equation of time is a correction to be added to apparent solar
time, as read on a sundial, to obtain mean solar time, as commonly
used. This difference is a consequence of the ellipticity and tilt of
the Earth's orbit, causing the irregular apparent movement of the Sun
across the sky. </p>
<p>D and T vary according to the time of year and can be obtained accurately from The Star Almanac or calculated approximately. </p>
<p></p>
<center><strong>Graph of Declination angle (D) versus Month</strong>
<p><img tabindex="0" src="salaattimes_files/decang.gif"></p>
<p><strong>Graph of Equation of Time(T) versus Month</strong></p>
<p><img tabindex="0" src="salaattimes_files/eoft.gif"></p></center>
<p>The following equations may be used to calculate the prayer times: </p>
<p class="separator" style="clear: both; text-align: center;" hashcode="" closure=""><a style="border-width: 0px; margin-left: 1em; margin-right: 1em; background-color: transparent; text-decoration: none;" href="http://www.nwis.org.uk/SalatCalculationFormula.jpg/SalatCalculationFormula-full.jpg" hashcode="" closure="" imageanchor="1"><img style="border-width: 0px;" tabindex="0" src="salaattimes_files/SalatCalculationFormula-full.jpg" hashcode="" closure="" galleryimg="no"></a></p><pre><br>where <br> <br>B= latitude of place <br>L= longitude of place <br>R= reference longitude (i.e. TIME BAND x 15) <br>H= height above sea level in metres <br>D= declination angle of sun from celestial equator (-ve in southern hemisphere)<br>T= equation of time <br>G= twilight angle <br> <br>Fajr = Z-V <br>Sunrise = Z-U <br>Zuhr = Z <br>Asr1 (Shafi) = Z+W <br>Asr2 (Hanafi) = Z+X <br>Maghrib/Sunset = Z+U <br>Isha = Z+V <br></pre><pre>The algorithms to calculate T and D are not shown here. These algorithms may be found in, </pre><pre>for example, Jean Meeus' Astronomical Algorithms. Zuhr time is calculated using equation 1. <br>The time for sunrise and sunset/ maghrib may be calculated by subtracting or adding <br>'U'(obtained from equation 2) to the Zuhr time respectively. </pre>
<p>Fajr and Isha times may be calculated by subtracting or adding 'V'
(obtained from equation 3) to the Zuhr time respectively. The term G
(twilight angle) in equation 3 is usually set to 18 degrees. For a
location with an extreme latitude, days in summer may be so long that
twilight persists between sunset and the next sunrise. Under these
circumstances, 'V' is undefined and Fajr and Isha have to be determined
using agreed principles of fiqh. </p>
<p>The start of Asr time (Shafi) may be obtained by adding 'W'
(obtained from equation 4) to Zuhr; Asr time (Hanafi) is calculated by
adding 'X' (obtained from equation 5) to Zuhr. </p>
<p><a href="" name="8. Software"></a></p>
<h2> </h2>
<h2>8. Software</h2>
<p>Dr. Monzur Ahmed's Website is at <a href="http://www.starlight.demon.co.uk/">http://www.starlight.demon.co.uk/</a></p>
<p><a href="http://www.salahtimes.com/">Salah Times.com</a> Website is probably one of the most user friendly websites for UK prayer time display </p>
<p><a href="http://www.salaattime.com/">Salaat Time </a>- this is a
Windows based program can calculate prayer times and Qibla direction
for any location on earth using the principles and techniques discussed
above. </p>
<p><a href="http://www.islamicfinder.org/athanDownload.php">Athan Software</a>. Athan Software is a Prayer Calculation program available from <a href="http://www.islamicfinder.org/">IslamicFinder.org</a></p>
<p><a href="http://www.icoproject.org/">Accurate Times.</a> This is the works of the Jordanian Astronomical Society (JAS) by Mohaamad Odeh and a member of the <em>Islamic Crescents' Observation Project (ICOP). </em></p>
<p><em>BBC Website Religion and Ethics tools, <a href="http://www.bbc.co.uk/religion/tools/calculator/">BBC Prayer Calculator</a></em></p>
<h2> </h2>
<h2>8. Summary</h2>
<ul>
<li>Zuhr, Asr (Shafi and Hanafi) and Maghrib times may be calculated unambiguously.
</li><li>Fajr and Isha times depend on twilight and require the adoption of a suitable<em> twilght angle</em>.
</li><li>Generally, a twilight angle of 18 degrees may represent a safe upper limit although opinions and practices vary.
</li><li>In locations at higher latitude, twilight may persist
throughout the night during some months of the year - here alternative
methods such as 1/7th night rule must be used to calculate fajr/isha
times. </li></ul>
<h2> </h2>
<h2>10. References</h2>1. Dr. Monzur Ahmed; README.TXT file of Prayer Time Calculator v2.5
<p>2. Dr. Mohammad Ilyas; Astronomy of Islamic Times for the Twenty-first Century, 1989; Mansell, London. </p>
<p>3. Dr. Mohammad Ilyas; A Modern Guide to Astronomical Calculations
of Islamic Calendar, Times & Qibla;1984,Berita Publishing Sdn Bhd.,
Kuala Lumpur, Malaysia </p>
<p>4. Moulana Yakub Qasmi and Tariq Muneer, Prayer Times for United
Kingdom & Ireland; 1989, Islamic Research Institute of Britain,
Dewsbury, UK. </p>
<p>5. Abdul Lateef Bin Abdul Aziz, Perpetual Prayer Time Table for the
Whole World; 1986, Published by Abdul Majeed Qureshi, Karachi,
Pakistan. </p>
<p>6. Jean Meeus, Astronomical Algorithms; 2nd ed; 1991; Willmann -Bell Inc; Richmond, USA. </p></div></div>
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