A similar narration (from another chain linking to) this chain is also reported.
Jami` at-Tirmidhi Book 2, Hadith 18
← Previous Hadith "I am the most knowledgeable among the people about the prescribed time of this prayer: Allah's Messenger would pray it when the moon set on the third (of the month)."

Jami` at-Tirmidhi Book 2, Hadith 17 Next Hadith → Allah's Messenger said: "If it were not that it would be a hardship on my Ummah, then I would have ordered you to delay Isha until the third of the night, or its half."

Jami` at-Tirmidhi Book 2, Hadith 19