Green's function (many-body theory): Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
Newer edit →
en>CosmosHua
 
No edit summary
Line 1: Line 1:
The name of the author is Figures but it's not the most masucline title out there. His wife doesn't like it the way he does but what he really likes doing is to do aerobics and he's been doing it for fairly a while. Years ago we moved to Puerto Rico and my family enjoys it. My working day job is a meter reader.<br><br>My web-site - [http://srgame.co.kr/qna/21862 at home std testing]
{{External links|date=March 2012}}
 
{{Islam}}
 
'''Salat times''' refers to times when [[Muslims]] perform prayers (''[[salat]]''). The term is primarily used for the five daily prayers plus the Friday prayer. According to Muslim beliefs, the salat times were taught by [[Allah]] to [[Muhammad]].
 
Prayer times are standard for [[Muslims]] in the world, especially the fard prayer times. They depend on the condition of the [[Sun]] and geography. There are varying opinions regarding the exact salat times, the [[Madh'hab|schools of Islamic thought]] differing in minor details. All schools agree that any given prayer cannot be performed before its stipulated time.
 
==Five daily prayers==
The five daily prayers are obligatory (''[[fard]]'') and they are performed at times determined essentially by the position of the Sun in the sky. Hence, salat times vary at different locations on the Earth. 
* [http://www.islamicity.com/ISLAMITV/?ref=1274 Video about Salat]
* [http://www.islamicity.com/mosque/salat/PRAYER-KATALOG2.pdf Printable Prayer Description]
 
===Fajr (pre-dawn)===
Fajr begins at subh saadiq - true dawn or morning twilight  when the morning light appears across the full width of the sky and ends at sunrise
 
===Dhuhr (midday)===
{{Main|Dhuhr}}
The Dhuhr prayer starts after the sun passes its [zenith], and lasts until Asr
 
===Asr (afternoon)===
{{Main|Asr}}
The Asr prayer starts when the shadow of an object is the same length as the object itself (or, according to [[Hanafi]] fiqh, twice its length) and lasts till sunset.  Asr can be split into two sections; the preferred time is before the sun starts to turn orange, while the time of necessity is from when the sun turns orange until sunset.
 
===Maghrib (sunset)===
{{Main|Maghrib}}
The Maghrib prayer begins when the sun sets, and lasts till the red light has left the sky in the west.
 
===Isha'a (night)===
{{Main|Isha'a}}
The Isha'a prayer starts when the red light is gone from the western sky, and lasts until the rise of the "white light" (fajar sadiq) in the east.  The preferred time for Isha'a is before midnight, meaning halfway between sunset and sunrise.
* [http://www.islamicity.com/multimedia/CyberTV/ch17/default.asp?inc=1.htm#Isha_Prayers Video Salat Isha'a] in Makkah and Madinah.
 
== Time calculation ==
[[File:Equation of time.png|thumb|Equation of time]]
[[File:Sun-declination.jpg|thumb|Declination of the sun]]
 
To calculate prayer times two astronomical measures are necessary, the declination of the sun and the difference between clock time and [[sundial clock]]. This difference being the result of the eccentricity of the earth's orbit and the inclination of its axis, it is called the Equation of time. The declination of the sun is the angle between sun's rays and the equator plan.<ref>[http://aa.usno.navy.mil/faq/docs/SunApprox.php Approximate Solar Coordinates]</ref>
 
In addition to the above measures, to calculate prayer times for a specific location we need its spherical coordinates.<ref>[http://praytimes.org/calculation/#Calculating_Prayer_Times Calculating Prayer Times]</ref>
 
In the following <math> T_Z </math> is the time zone, and <math>T_E</math> the time equation value. <math> L </math> and <math> D </math> are respectively the [[Longitude]] and the [[Latitude]] of the considered point.
 
An other important equation gives the time difference between when the sun hits its highest point in the sky (Dhuhr time) and any other angle <math>\alpha</math>, as follow:
<math> T(\alpha) = {1 \over 15} \arccos \left( {-\sin(\alpha)-\sin(L)*\sin(D) \over \cos(L)*\cos(D)} \right) </math>
 
* Midday (Dhuhr) time is easily obtained. When the sun reaches the mid sky, time is given by: <math>T_{Dhuhr} = 12 + T_Z - (L/15 + T_E)</math>
* Sunrise (Chorok) and Sunset (Maghreb) time are given by <math> T(0.833) </math>, in fact it is the astronomical sunset/sunrise that occurs for <math>\alpha = 0 </math>. 0.833 is a slight correction that gives the actual time. So <math>T_{Chorok} = T_{Dhuhr} - T(0.833)</math> and <math>T_{Sunset} = T_{Dhuhr} + T(0.833)</math>.
If we consider the elevation of the point we should add another correction to the constant <math> 0.0347 \times \sqrt{h} </math>.
* For Fajr and Isha many conventions about the angle <math>\alpha</math> exist. It is of 17 and 18 degrees respectively for Fadjr and Isha prayers according to the [[Muslim World League]].
* For Asr time according to the majority of Muslim schools, including [[Shafi'i]], [[Maliki]], [[Ja'fari]], and [[Hanbali]], it is when the length of an object shadows became equal to its length plus the length of its shadow at noon. The Hanafi schools states that the time of Asr is when an object's shadow reaches two times the length of the object itself, plus the length of its shadow at noon. The time the shadow of an object reaches <math>T</math> times its length is given by the equation: <math>A(T) =  {1 \over 15} \arccos \left( {\sin(\arccot(t+\tan(L-D)))-\sin(L)*\sin(D) \over \cos(L)*\cos(D)} \right)</math>.
* It is called for the Maghrib prayer when the sun is completely folded behind the horizon, plus 3 minutes by precaution.
 
{{clear}}
 
==Friday prayer==
{{Main|Jumu'ah}}
The Friday prayer replaces the dhuhr prayer performed on the other six days of the week. The precise time for this congregational prayer varies with the mosque, but in all cases it must be performed after the dhuhr and before the asr times. If one is unable to join the congregation, then they must pray the dhuhr prayer instead. This
salat is compulsory to be done with ja'maat for men. Women have the option to perform Jumm'ah in the mosque or to pray dhuhr
* [http://www.islamicity.com/multimedia/CyberTV/ch17/default.asp?inc=1.htm#Friday_(Jumuah)_Prayers Video Salat Jumah/Friday] in Makkah and Madinah.
 
==Other salat==
 
===Eid prayers===
Eid-ul-Adhaa and Eid-ul-Fitr
{{Main|Salat al Eid}}
* [http://www.islamicity.com/multimedia/CyberTV/ch17/default.asp?inc=1.htm#Eid-ul_Fitr_Prayers Video Salat Eid-ul-Fitr] in Makkah and Madinah.
* [http://www.islamicity.com/multimedia/CyberTV/ch18/default.asp?inc=1.htm#Salat Video Salat Eid-ul-Adhaa] in Makkah and Madinah.
 
===Taraweeh===
Salat during Ramadhan, performed at night after Isha (night) prayer. Usually performed in congregation.
* [http://www.islamicity.com/multimedia/CyberTV/ch17/default.asp?inc=8.htm#Taraweeh_Prayer_1429 Video Salat Taraweeh] in Makkah and Madinah, Ramadan 1429 AH or 2008 AC.
 
===Janaaza===
Salat at a funeral
 
==References==
 
{{reflist}}
* [http://ig.internetplus.biz/prayertimes/en- Prayer times] for many countries
* [http://www.prayertimes.info Prayer Times] Prayer times are calculated based location of the IP address.
* [http://www.islamicfinder.org/world.php Prayer Times] for more than 6 million cities in 252 countries in the world.
* [http://www.islamicity.com/prayertimes Printable Prayer Times] for more than 3.7 million cities in 200 countries in the world as well as latitude and longitude inputs.
*[http://reminder.salaahtimes.co.za Salaah Time Reminders on Twitter for various Cities in South Africa]
*[http://www.al-islam.org/encyclopedia/chapter7/6.html Salat according to some Islamic schools of thought]
 
{{Islamic prayer}}
 
[[Category:Salat]]
[[Category:Islam stubs]]

Revision as of 23:22, 4 November 2013

Template:External links

Template:Islam

Salat times refers to times when Muslims perform prayers (salat). The term is primarily used for the five daily prayers plus the Friday prayer. According to Muslim beliefs, the salat times were taught by Allah to Muhammad.

Prayer times are standard for Muslims in the world, especially the fard prayer times. They depend on the condition of the Sun and geography. There are varying opinions regarding the exact salat times, the schools of Islamic thought differing in minor details. All schools agree that any given prayer cannot be performed before its stipulated time.

Five daily prayers

The five daily prayers are obligatory (fard) and they are performed at times determined essentially by the position of the Sun in the sky. Hence, salat times vary at different locations on the Earth.

Fajr (pre-dawn)

Fajr begins at subh saadiq - true dawn or morning twilight when the morning light appears across the full width of the sky and ends at sunrise

Dhuhr (midday)

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The Dhuhr prayer starts after the sun passes its [zenith], and lasts until Asr

Asr (afternoon)

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The Asr prayer starts when the shadow of an object is the same length as the object itself (or, according to Hanafi fiqh, twice its length) and lasts till sunset. Asr can be split into two sections; the preferred time is before the sun starts to turn orange, while the time of necessity is from when the sun turns orange until sunset.

Maghrib (sunset)

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The Maghrib prayer begins when the sun sets, and lasts till the red light has left the sky in the west.

Isha'a (night)

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The Isha'a prayer starts when the red light is gone from the western sky, and lasts until the rise of the "white light" (fajar sadiq) in the east. The preferred time for Isha'a is before midnight, meaning halfway between sunset and sunrise.

Time calculation

Equation of time
Declination of the sun

To calculate prayer times two astronomical measures are necessary, the declination of the sun and the difference between clock time and sundial clock. This difference being the result of the eccentricity of the earth's orbit and the inclination of its axis, it is called the Equation of time. The declination of the sun is the angle between sun's rays and the equator plan.[1]

In addition to the above measures, to calculate prayer times for a specific location we need its spherical coordinates.[2]

In the following is the time zone, and the time equation value. and are respectively the Longitude and the Latitude of the considered point.

An other important equation gives the time difference between when the sun hits its highest point in the sky (Dhuhr time) and any other angle , as follow:

If we consider the elevation of the point we should add another correction to the constant .

50 year old Petroleum Engineer Kull from Dawson Creek, spends time with interests such as house brewing, property developers in singapore condo launch and camping. Discovers the beauty in planing a trip to places around the entire world, recently only coming back from .

Friday prayer

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church. The Friday prayer replaces the dhuhr prayer performed on the other six days of the week. The precise time for this congregational prayer varies with the mosque, but in all cases it must be performed after the dhuhr and before the asr times. If one is unable to join the congregation, then they must pray the dhuhr prayer instead. This salat is compulsory to be done with ja'maat for men. Women have the option to perform Jumm'ah in the mosque or to pray dhuhr

Other salat

Eid prayers

Eid-ul-Adhaa and Eid-ul-Fitr Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church.

Taraweeh

Salat during Ramadhan, performed at night after Isha (night) prayer. Usually performed in congregation.

Janaaza

Salat at a funeral

References

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

Template:Islamic prayer

  1. ↑ Approximate Solar Coordinates
  2. ↑ Calculating Prayer Times
Retrieved from "https://en.formulasearchengine.com/index.php?title=Green%27s_function_(many-body_theory)&oldid=15503"