(8) بَاب بَيَانِ أَنَّ الدُّخُولَ فِي الصَّوْمِ يَحْصُلُ بِطُلُوعِ الْفَجْرِ وَأَنَّ لَهُ الْأَكْلَ وَغَيْرَهُ حَتَّى يَطْلُعَ الْفَجْرُ وَبَيَانِ صِفَةِ الْفَجْرِ الَّذِي تَتَعَلَّقُ بِهِ الْأَحْكَامُ مِنْ الدُّخُولِ فِي الصَّوْمِ وَدُخُولِ وَقْتِ صَلَاةِ الصُّبْحِ وَغَيْرِ ذَلِكَ
This hadith has been narrated by Sulaiman al-Taimi with the same chain of transmitters (but with a slight variation of words) that he (the Holy Prophet) said:
The dawn is not like it as it is said; he then gathered his fingers and lowered them. But he said, it is like this (and he placed the index finger upon the other one and spread his hand).
Reference: Sahih Muslim 1093 b
In-book reference: Book 13, Hadith 48
USC-MSA web (English) reference(deprecated numbering scheme): Book 6, Hadith 2405