بررسي رابطه انحراف قبله مراكز مذهبي با انحراف مغناطيسي آن

Analysis of the Relationship between Qibla Direction Deviations of Religious Centers with Magnetic Inclination

امروزه خطا در پياده كردن قبله توسط بعضي نقشه برداران مشكلاتي را به دنبال داشته است. يكي از دلايل وجود انحراف زاويه اي با جهت دقيق قبله در بناي مراكز مذهبي نظير مساجد، مقبره ها و قبور مسلمانان، مي تواند ناشي از وجود زاويه انحراف مغناطيسي در زمان ساخت بنا باشد. خصوصاً تغييرات زاويه انحراف مغناطيسي در اثر عوامل مختلف از جمله طوفان هاي مغناطيسي و ديگر خطاهاي موجود و تاثير مستقيم بر روي قطب نماي مورد استفاده در تعيين قبله، مي تواند بر انحراف گفته شده بيافزايد. در اين مقاله با انتخاب تعداد زيادي از مراكز مهم مذهبي داخلي و خارجي، ضمن محاسبه دقيق آزيموت قبله از روي مختصات جغرافيايي آن نقطه و مختصات جغرافيايي كعبه، آزيموت فعلي آن نقطه به كمك نرم افزار گوگل ارث استخراج و مقدار زاويه انحراف قبله در آن نقطه محاسبه شده است. سپس به كمك مدل مغناطيسي WMM2015 مقدار انحراف مغناطيسي براي هر نقطه با توجه به تاريخ ساخت آن بنا به دست آمده و در نهايت ضريب همبستگي بين زواياي انحراف قبله و انحراف مغناطيسي تعيين شده است. در انتها با دسته بندي نقاط در مناطق مختلف، مشخص شده است كه تعداد زيادي نقاط داراي همبستگي بالاي 60 درصد بوده و در مناطقي كه اين همبستگي كم است، احتمالاً قدمت بالاي بنا و عدم استفاده از قطب نما در زمان قديم و تاثير ديگر خطاها مثل عدم استفاده از روش دقيق تعيين موقعيت، منجر به انحراف قبله شده است.

One of the reasons for the angular deviation in the construction of religious organization such as mosques, tombs and graves of Muslims with the precise direction of the qibla at these points can be due to the angle of the magnetic inclination at the time of construction. Particularly, the changes in the angle of the magnetic inclination due to various factors, such as solar magnetic storms and other errors in the compass, can add to this inclination. Because of the invention of the compass about 400 years ago, this device was used to determine the direction of the qibla for each building. Inappropriate use of this device has caused the deviation of the qibla from several degrees to many degrees. In this paper, a large number of the well-known religious organization was selected. For this selected area first, the azimuth of qibla was calculated by using the geographic position of each point and Ka’aba. Second, then current azimuth was retrieved by using Google Earth software. Finally, the Qibla deviation angle was calculated. Here, the accuracy of Azimuth's estimation along the Qibla direction of each building from the Google Earth software is also considered. For this purpose, the accuracy of the azimuth extraction of each wall is calculated by the length of the building wall. Despite a precision of 2 degrees in a 68-meters distance, but with azimuth extraction repetition, accuracy below the degree (average 0.5 °) can be achieved. In the following, the magnetic inclination of the Qibla at selected point was calculated by a magnetic model WMM2015 according to the date of its construction, finally, the correlation coefficient between angles of Qibla direct deviation and magnetic inclination were calculated The World Magnetic Model (WMM) is a joint product of the United States' National Geospatial-Intelligence Agency (NGA) and the United Kingdom's Defense Geographic Centre (DGC). The WMM Model is the standard model using for navigation, attitude and heading reference systems using the geomagnetic field. It is also used widely in civilian navigation and heading systems such as determining the magnetic inclination at every point. The model is produced at 5-year intervals, with the current model expiring on December 31, 2019. Finally, we have categorized the points of different regions and have shown that a large number of points have a correlation of over 60%.These points have been in groups that are closest to the city of Mecca. The longer distance, the less correlation and areas with low correlation, probably it is cause to the lack of using the compass in the ancient times or the effects of other errors that there led to Qibla deviation including being away from the city of Mecca. Therefore, it is possible to link the error of the Qibla deviation of the religious centers to two criteria, distances from the city of Mecca and the oldity of the building such as the impossibility of using the compass and the exact coordinate determination for these points.