In this paper, I focus on the transmission of the Indian astronomical tradition founded by Āryabhaṭa (fl. ca. 499 CE) known as the Ārdharātrikapakṣa or “midnight school” to Sasanian and early Islamic Iraq. Drawing on evidence in Middle Persian and Arabic heretofore ignored or insufficiently emphasized, I add further support and nuance to the idea, first proposed by David Pingree and E. S. Kennedy, that the Ārdharātrikapakṣa reached the Sasanian empire through a Middle Persian work called the Arkand, which was still known in Islamic times to authors including Māshāʾallāh (d. ca. 815) and al-Bīrūnī (d. 1030).