Summary Excerpts
In general the average muslim does not need to make this calculation. They should simply follow their local masjid and the majority of the muslims in their area/ land. Unity of muslims is better than discord over the differences of opinion.
It is for those who need to make this decision to consider the differences of opinion and come to a judgement for their locality/ communities. The differences are primarily an issue when the land in question approaches the polar regions and is far from the equator. In such regions it is possible to have differences of a whole hour or so between the different calculations.
The time in question is the beginning of fajr as this denotes the time at which suhoor must end. The Quran clearly states that one may eat until the white thread of dawn is distinguished from the black thread of the night. However this phenomenon is not purely dependent on the sun. It can be dependent of one’s location, how observable the horizon is, one’s own eyesight and other such factors.
The astronomical dawn i.e. the point at which the night ends and the twilight of dawn begins is considered when the sun is 18 degrees below the horizon. For this reason traditionally and many Islamic apps today use 18 degrees as the basis as the time of imsak i.e. the point at which the suhoor meal must be completed.
However the astronomical dawn does not strictly meet the criterion of the Quranic imsak. There are too many variables that determine when exactly the whitishness of the true dawn occurs on a given day.
Some may say that one should be safe and make imsak a bit early, but for those who do not have much time to eat, we need to consider their needs. Furthermore, it is a sunnah to eat until the adhan is given.
In fact many studies into this have concluded that imsak occurs after 18 degrees and when the sun is more in the region of 15 degrees below the horizon and even upto 13 degrees depending on one’s location.
Therefore in conclusion, the calculation of suhoor can vary for legitimate reasons and because the Earth is not one uniform globe. And the best advice is to follow your community and the majority.
Those who wish to understand further should watch the video for Shaykh Yasir Qadhi‘s exact words.
And Allah knows best.
