Determination of Qibla direction with Kompas

This title ought to more complete: Consequence of Determining Qibla direction with Kompas if without correction. A Moslem before praying in new place, usually measure angle of Qibla direction with compass, although just ascertaining (or calibrating), either in house and also mosque (because proven there are mosque that is is not faces Qibla like Masjid Agung Yogyakarta, read here) 

This angular value obtained from computer programs which many dispersions in internet (for example Accurate Times, Athan Basic, Salaat time, Salat & Qibla from Napier University, WinHisab from DEPAG etc) or letter from MUI. Accurate Times say that angle of Qibla direction from Jakarta: 295,1° FROM TRUE NORTH. 

 Many people assumes that tip of compass needle to show True north, and then does unidirectional shalat with value 295,1° which as described in compass. But this is wrong. North needle of compass shows Magnetic North direction. 

  Variation Compass needle always follows direction of earth's magnetic field, though in every place of earth magnetic current is not always shows True north because its complex influence on the surface of earth. Angle between Magnetic North and northly actually (True North) named Variation (also called Magnetic Declination). This variation always different every time and place. Tt is hard, not all program/ formal letter figures in value to correct this. So where we get it? In every map usually is mentioned variation value, for example topography map West Java made by Army Map Service (NSVLB), Corps of Engineers, US army express; “1955 Magnetic Declination for this sheet varies from 0°15 ' eaterly for the center of the west edge to 1°00 ' easterly for the center of the east edge. Mean annual change is 0°02 ' westerly” Free meaning, The year 1955, Various in Jakarta 0°15 ' easterly, average of 0°02 ' to west per annum. So its calculation:

Now 2008,
difference from the year 1955 to become 
53 years = 1°44 ' to West.

Total variation;
=  0°15 ' easterly + 1°44 ' to West
=  1°29 ' to West.

Because The Variation towards west, hence value which
shown by BIGGER compass needle from value posed at from True North.
Becomes:

295,1° + 1°29' = 296,6°

The formula;
sign (-) if variation to west ( West),
sign (+) on the contrary.

Deviation Deviation is mistake of compass needle read which caused by objects influence around compass, for example iron, machine or electronic equipments (HP, MP3 player etc). Deviation can be disregarded if we are sure no objects influential in around. Following example of differ Variation every town from the same source map: Sampit = 2°00 ' easterly, average of per annum can be disregarded. Surabaya and Malang = 2°05 ' easterly, average of 0°02 ' to west per annum (map the year 1955). While from program Mooncalc made in Dr. Monzur Ahmed: Galela, Halmahera North = 1°09 ' easterly Banda aceh = 1°00 ' to West Kobe, Japan = 7°07 ' easterly (thus imprecise when dr.Helfi praying with Qibla direction of 290,1° because ought to 283,1° Conclusion and Suggestion - Qibla Direction from Jakarta shown by compass needle 296,6° - Not all program/ formal letter figures in value to correct this, because its value differs in in every time and place. Hence more suggestingly is determination of direction with help of the sun shadow which the scheme and mode of action can be read in: Scheme only need to be printed then is kept in purse :P . If you are enthusiastic in “high resolution” scheme can contact me via e-mail (nafanakhun@gmailcom). Finally, this article do not be meant to complicating situation, but of course above is the fact. Hopefully useful. Genghis Khun % Reference 1. Program Accurate Times ( http://www.jas.org.jo/accut.html) 2. Natural Resources Canada ( http://gsc.nrcan.gc.ca/geomag/field/magdec_e.php) 3. http://www.sailingissues.com/navcourse3.html 4. http://www.lib.utexas.edu/maps/ams/indonesia 5. Program Mooncalc ( http://www.starlight.demon.co.uk/mooncalc)