Is the time for breaking the fast for the fasting person at sunset or when the redness in the eastern sky disappears?

There is no doubt that the time for breaking the fast is at sunset; because it is the beginning of the night, and Allah Almighty has said: ﴿ثُمَّ أَتِمُّوا الصِّيَامَ إِلَى اللَّيْلِ﴾[1]; “Then complete the fast until the night.” Therefore, there is no justification for the Shias’ regular practice of delaying the breaking of the fast until the redness in the eastern sky disappears. A similar practice has been reported from some of their extremists known as the Khattabiyyah; as one of our companions informed us, he said: «صَلَّى الْمَنْصُورُ صَلَاةَ الْمَغْرِبِ، ثُمَّ سَمِعَ أَذَانًا، فَقَالَ: مَا هَذَا؟! قُلْنَا: هَذَا أَذَانُ الشِّيعَةِ! لَا يُؤَذِّنُونَ حَتَّى يَرْتَفِعَ اللَّيْلُ! فَقَالَ: غَلَبَ عَلَيْهِمُ الْخَطَّابِيَّةُ»; “Mansoor performed the sunset prayer. Then he heard an Adhan. So he said: ‘What is this?!’ We said: ‘This is the Adhan of the Shias! They do not call to prayer until the night rises!’ He said: ‘The Khattabiyyah have prevailed over them.’” It has been narrated from the Prophet that he said: «لَا يَزَالُ النَّاسُ بِخَيْرٍ مَا عَجَّلُوا الْفِطْرَ»[2]; “People are always upon goodness as long as they hasten to break the fast.” In another narration, he said: «عَجِّلُوا الْفِطْرَ فَإِنَّ الْيَهُودَ يُؤَخِّرُونَ»[3]; “Hasten to break the fast, for the Jews delay.” It has been narrated from Abu Atiyyah that he said: «دَخَلْتُ أَنَا وَمَسْرُوقٌ عَلَى عَائِشَةَ، فَقُلْنَا: يَا أُمَّ الْمُؤْمِنِينَ! رَجُلَانِ مِنْ أَصْحَابِ مُحَمَّدٍ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ، أَحَدُهُمَا يُعَجِّلُ الْإِفْطَارَ وَيُعَجِّلُ الصَّلَاةَ، وَالْآخَرُ يُؤَخِّرُ الْإِفْطَارَ وَيُؤَخِّرُ الصَّلَاةَ، قَالَتْ: أَيُّهُمَا الَّذِي يُعَجِّلُ الْإِفْطَارَ وَيُعَجِّلُ الصَّلَاةَ؟ قَالَ: قُلْنَا: عَبْدُ اللَّهِ يَعْنِي ابْنَ مَسْعُودٍ، قَالَتْ: كَذَلِكَ كَانَ يَصْنَعُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ»; “I went with Masruq to Aisha. Then we said: ‘O Mother of Believers! Two men from the companions of Muhammad one hastens to break the fast and perform prayer, and the other delays breaking the fast and performing prayer.’ She said: ‘Which one hastens to break the fast and perform prayer?’ We said: ‘Abdullah, meaning ibn Mas‘ud.’ She said: ‘The Messenger of Allah used to do the same.’” Abu Kuraib has added: «وَالْآخَرُ أَبُو مُوسَى يَعْنِي الْأَشْعَرِيَّ»; “The other (who delayed breaking the fast and performing prayer) was Abu Musa al-Ash‘ari.”[4]

Yes, a few minutes of precaution poses no issue, and we found that His Eminence Allamah Mansoor Hashemi Khorasani (may Allah Almighty protect him) took a level of precaution equal to one astronomical degree, and each degree is equal to five minutes.