"I am the most knowledgeable of people about the time of the 'Isha' prayer. The Prophet ﷺ used to pray it when the moon set on the third night of the month." (Using translation from Nasāʾī 528)
أَنَا أَعْلَمُ النَّاسِ بِمِيقَاتِ هَذِهِ الصَّلَاةِ عِشَاءِ الْآخِرَةِ كَانَ رَسُولُ اللهِ ﷺ «يُصَلِّيهَا لِسُقُوطِ الْقَمَرِ لِثَالِثَةٍ»