Theodore's main work is his Astronomical Tribiblos, in three books, whose autograph manuscript is preserved (Vaticanus gr.
The work deals with an assortment of mathematical and astronomical issues and draws from some earlier Greek authors like George Pachymeres and Theodore Metochites.
Finally, in book 3 he devotes himself to Persian astronomy, drawing especially from George Chrysokokkes, whose work he corrected in many places.
In all of them, he explicitly condemns Astrology, dissociating his Astronomy from the Persian tradition represented by Chrysokokkes.
The pedagogical character of the Tribiblos is obvious and it may have been used to give senior astronomy training to the Byzantine clergy.