A second-order interpolation scheme described in the Zij-i Ilkhani / Javad Hamadani-Zadeh.
Note:
Con la trad. inglese di passi scelti dal ms. orig.
Abstract:
"The purpose of this note is to present an English translation and a commentary on the section of al-Tusi's "Zij-i Ilkhani" which contains [the interpolation] method and applies it to give the true longitude of a planet."
Historia mathematica Vol. 12 (1985), p. 56-59