I am the one who is best informed of the time of this prayer, i.e. the night prayer. The Messenger of Allah ﷺ used to offer it at the hour when the moon went down on its third night.
أَنَا أَعْلَمُ النَّاسِ بِوَقْتِ هَذِهِ الصَّلاَةِ صَلاَةِ الْعِشَاءِ الآخِرَةِ كَانَ رَسُولُ اللَّهِ ﷺ يُصَلِّيهَا لِسُقُوطِ الْقَمَرِ لِثَالِثَةٍ