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View Full Version : qibla -- the great-circle angle toward Mecca



Silas
2002-Mar-31, 08:23 PM
It occurred to me that most of our "against the mainstream" religious astronomy has been Christian. I wanted to "level the playing field" just a bit, and supply a source to a very nice summary of the mathematical equations that are used to determine the angle toward Mecca. A VERY nice summary of this can be found by going to http://patriot.net/~abdali/ftp/index.html and downloading qibla.pdf.

This would be little more than a religious source -- perhaps of interest but not necessarily appropriate here -- except that the equations can be generalized for any point on earth. Thus, for whatever reason, if one wanted to determine the exact direction to Rome, or Beijing, or one's grandmother's house, the equations in this reference will provide them.

I hope that this commingling of the sacred and the profane -- and the mathematical -- make this source of interest to the board at large.

Silas

GrapesOfWrath
2002-Mar-31, 11:42 PM
It appears that the author is engaged in a religious dispute--he applied spherical trig to the problem, and his critics just used the Mercator projection.

Because he ignored the oblateness of the Earth, his critics say he can't be trusted! On the other hand, the Earth is about as round as a cheap billiard ball (it's not as round as an expensive one--but it is smoother).

Drogulus
2002-Apr-04, 06:53 PM
Years ago, in his column in Scientific American, Martin Gardner featured a "Mecca Map" - a map using a projection such that the bearing from some other point to Mecca as measured on the map was the same as the true bearing. Of course, you can do the same with any point as your "Mecca". The one Gardner printed gave the bearing to the West's Mecca, i.e. Wall Street, marked on the map with a large $.

Bob
2002-Apr-04, 07:13 PM
Supposedly true story: the private jet of a Saudi prince is equipped with a throne which is automatically faced toward Mecca no matter what the heading of the plane might be.

2002-Apr-05, 07:28 AM
On 2002-03-31 15:23, Silas wrote:
It occurred to me that most of our "against the mainstream" religious astronomy has been Christian. I wanted to "level the playing field" just a bit, and supply a source to a very nice summary of the mathematical equations that are used to determine the angle toward Mecca. A VERY nice summary of this can be found by going to http://patriot.net/~abdali/ftp/index.html and downloading qibla.pdf.

This would be little more than a religious source -- perhaps of interest but not necessarily appropriate here -- except that the equations can be generalized for any point on earth. Thus, for whatever reason, if one wanted to determine the exact direction to Rome, or Beijing, or one's grandmother's house, the equations in this reference will provide them.

I hope that this commingling of the sacred and the profane -- and the mathematical -- make this source of interest to the board at large.

Silas : HUb' 1:17 A.M. its 700+k and the system i
connect thru has a timer set for 5 min = about 400k max
So for me.. it just takes to much time to do. [my 0pollogy to their.system.7]

Simon
2002-Apr-05, 10:32 AM
On 2002-04-04 14:13, Bob wrote:
Supposedly true story: the private jet of a Saudi prince is equipped with a throne which is automatically faced toward Mecca no matter what the heading of the plane might be.


Honestly, I wouldn't be particularly surprised if this were true.