After the mid Heian period, such direct access to the emperor was only allowed to the Abe clan whose hereditary occupation was tenmon hakase and the Nakahara clan which was kyokumu (the chief secretary of the Daijokan, or Grand Council of State); incidentally, the Nakahara clan had assumed the role of tenmon misso from Mochitada NAKAHARA in the tenure of Emperor Daigo (afterwards in 972, he was granted the family name of NAKAHARA along with Uzo NAKAHARA [中原有象] of the head family and originated the clan), allegedly because, besides the clan's hereditary occupation of Geki [Secretary of the Grand Council of State], it inherited the family learning of Myogo-do [the study of Confucian classics] and used many Chinese classics as source books, many of which contained elucidation of astronomical phenomena so that the clan produced many persons well versed in tenmondo.
また、上奏する資格も平安時代中期以後には天文博士を世襲した阿倍氏と局務の中原氏の両家のみに限定されるようになっていく（なお、中原氏の天文密奏は醍醐天皇の時代の中原以忠（後に天禄2年（972年）に宗家の中原有象とともに中原のカバネを与えられて同氏の祖となる）に遡り、同氏本来の外記の職務とは別に同氏が家学としていた明経道の出典である漢籍には天文現象の解釈に関する記述が含まれていることが多く、天文道に通じた人物を輩出することが多かった事によるとされている）。