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This type of calculation is based on the Arabic calendar. First of all calculations should be made to determine in which zodiac constellation is the Sun positioned. Then in order to find out the position of Moon on a particular date of the Arabic calendar, the date should be multiplied by 13. 26 should be added to the sum and the result should be divided by 30. The quotient and the remainder are used to determine the exact position of the Moon in the sky.
For example: If you want to find out the position of Moon as on 22nd April 1965 (19 Zil hajj 1384) then you should multiply 19 by 13. You will get 247 to which you should add 26. The result will be 273. Now, if you divide 273 by 30 then the quotient will be 9 and the remainder will be 3. Since Sun is in Taurus (22nd April - 21st May) at this time of the year so the Moon, as per the above calculations, will be in the 9th zodiac constellation, starting from Taurus, i.e. Capricorn at 3 degrees.
There is another method of calculation the position of the Moon.
An example: If you want to know the location of Moon on 19th zil Hajj then multiply 19 by 2 and you will get 38. Then add 5 to this and the result will be 43. Now subtract 5 from each burj, starting from the burj in which the Sun is positioned. In this case the Sun is in Taurus. Hence, starting from Taurus we will reach Capricorn (40/8=5) and the remainder will be 3. This 3 will be moved on to the next zodiac, i.e. Capricorn. So, the Moon will said to be in Capricorn at 3 degrees.
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