Language:
كتاب مواقيت الصلاة
9  
Times of the Prayers
(13)
Chapter: The time of the Asr prayer
(13)
باب وَقْتِ الْعَصْرِ
Sahih al-Bukhari 545

Narrated `Aisha:

Allah's Messenger (ﷺ) used to offer the `Asr prayers at a time when the sunshine was still inside my chamber and no shadow had yet appeared in it.

حَدَّثَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم صَلَّى الْعَصْرَ وَالشَّمْسُ فِي حُجْرَتِهَا، لَمْ يَظْهَرِ الْفَىْءُ مِنْ حُجْرَتِهَا‏.‏
Reference : Sahih al-Bukhari 545
In-book reference : Book 9, Hadith 22
USC-MSA web (English) reference : Vol. 1, Book 10, Hadith 520
  (deprecated numbering scheme)