Narrated Aisha (radiyallaahu-anhaa): Bilaal used to pronounce the Adhaan at night, so Allaah’s Messenger (sallal-laahu-alayhi-wasallam) said, ‘’Carry on taking your meals (eat and drink) til Ibn Umm Maktoom pronounces the Adhaan, for he does not pronounce it till it is dawn. [Saheeh Al-Bukhaari Vol: 3 Hadeeth No: 1918, 1919; Muhsin khan]

Imaam Abdul Azeez Bin Baaz (rahimahullaah) stated concerning the interval between the two Adhaans: ”(It is) a short time period.” [For further details see: Al-Hulalul Ibreeziyyah Min At-Taleeqaat Al-Baaziyyah Alaa Saheeh Al-Bukhaariy: Vol:2: foot note 1]