(2) باب الْحَالِ الَّتِي يَجُوزُ عَلَيْهَا اسْتِقْبَالُ غَيْرِ الْقِبْلَةِ
It was narrated that Abdullah said:
"The messenger of Allah (peace be upon him) used to pray atop his mount while traveling, facing whatever direction it was facing, and he would pray witr atop it, but he did not pray the prescribed prayers atop it ".
Reference: Sunan an-Nasa'i 744
In-book reference: Book 9, Hadith 3
English translation: Vol. 1, Book 9, Hadith 745