A Scientific Article
A Professor in the College of Education for Pure Sciences/Department of Physics, An Asst. Prof. (Doaa Diaa Abboud) obtained the acceptance to publishing a scientific article entitled (Criteria for the vision of crescents and the crescent of the blessed month of Shawwal for the year 2021 AD – 1442 AH) by the Scientific Articles Committee at Karbala University. The article is subject to all terms of publication. Asst. Prof (M.M. Doaa Diaa Abboud) mentioned that the sighting of the crescent affects a large number of factors, including, but not limited to, astronomical factors, and these will be explained and clarified briefly in this article, including geographical factors such as the presence of the observer in a geographical area, For example, a plain, a mountain, a valley, or an area at sea level, and so on, which affects the factor of the crescent’s height above the horizon. Also, weather factors such as the area to suffer from rain, heavy clouds, dust or fog, and others, affect the clarity of vision and the intensity of illumination. Of course, it is very important to know the generally agreed-upon astrological factors, namely:
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Age of the crescent: In general, no previous sighting of the crescent was recorded at an age of fewer than 15 hours with the naked eye or less than 12 hours with a telescope, and generally, it is usually more than 22 hours old.
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Angular height from the horizon: that is, the angle observed between the crescent and the horizon, and it must usually be not less than 5 degrees at least for the observer with the naked eye.
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Residency time: It represents the least observable time during which the crescent stays before setting on the horizon line, and in general, its time is estimated that it should not be less than 35 minutes, so less than that time makes it difficult to achieve the monitoring process.
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Note that the term of the birth of the crescent differs from the term of the age of the crescent, as the birth of the crescent is the exit of the moon from the phase of the new moon to the phase of the crescent after the separation of the conjunction between the sun and the moon at an angle that must not be less than 8 degrees, and this angle is called the angle of elongation between the moon and the sun.