At the end of Heian period, the Abe clan began to monopolize the roles of tenmon hakase and that received the imperial decree constituting the mission as the medium of tenmon misso, however, both the Abe clan's deep involvement in Onmyodo, the other family learning of the clan and the internal strife within the clan confused tenmon misso.
更に平安時代末期になると、安倍氏によって天文博士の地位と天文密奏宣旨の独占が行われるようになるが、安倍氏のもう1つの家学である陰陽道との密着と安倍氏内部の内紛が天文密奏に混乱を与えた。