Even the suggestion that the spherical earth was considered legit because of the Sphere of Sacrobosco and Ptolemaic astronomy is quite damaging to the true faith, since such writings were not well received by the Church.
"The “Commentary on the Sphere” was specifically condemned to be burned in 1327 at the same time as Cecco. Cecco also composed a long poem in Italian on the nature of the universe, with a focus on astrology and magic, called l’Acerba. This was also condemned by the Inquisition at the time of his execution.
The Sphere of Sacrobosco was a very popular medieval and Renaissance textbook on Ptolemaic astronomy, composed by an English astrologer/astronomer and mathematician, John of Sacrobosco in the 13th century. Since the geocentric Ptolemaic astronomy was the basis of traditional astrology, the Sphere of Sacrobosco was a key introductory text for astrologers covering the basics of the celestial circles, poles, meridian, ecliptic, the Zodiac and its signs and the movement of the planets." --Wikipedia
So, these heretical teachings were so bad, the Catholic Church actually burned Cecco at the stake for promoting them. Not only that, even Wiki recognizes that Ptolemaic astronomy was the basis of astrology.