Cfr. Dyson, F. W. (). The distribution in space of the stars in Carrington's Circumpolar Catalogue. Monthly Notices of the Royal Astronomical Society. 73 (5). p.342. doi:10.1093/mnras/73.5.334. bibcode:1913MNRAS..73..334D: “[paragrapho 14, pagina 342] Taking the unit of distance R* to be that corresponding to a parallax of 1″·0 [… Annotatio:] * There is need for a name for this unit of distance. Mr. Charlier has suggested Siriometer, but if the violence to the Greek language can be overlooked, the word Astron might be adopted. Professor Turner suggests Parsec, which may be taken as an abbreviated form of ‘a distance corresponding to a parallax of one second’.”
Cfr. Selvaggi, Philippus (). Cosmologia. Romae: Pontificia Universitas Gregoriana. ann.2, p.336: “Primae distantiae stellares calculatae sunt fere eodem tempore a T. Henderson(en), F. G. W. Struve et F. W. Bessel (1837–1838); stella nobis propinquior α Centauri distat fere tercenties millies magis quam Terra a Sole, id est circiter 4·1013km, seu paulo magis quam 4 annis lucis. Unitas usualis pro distantiis stellaribus est distantia percursa a luce uno anno, quae est fere 1013km. At «unitas astronomica» vocatur distantia media inter Terram et Solem, quae est circiter 150 milliones km; saepe etiam adhibetur parsec, seu distantia in qua parallaxis obiecti considerati est unius secundi: scilicet, quia parallaxis est translatio annua, quae in stellis observatur propter motum Terrae circa Solem, parsec est distantia in qua unitas astronomica apparet sub angulo unius secundi: 1 parsec = 3.258 a. 1. = 3.09·1013Km.”
Cfr. Dyson, F. W. (). The distribution in space of the stars in Carrington's Circumpolar Catalogue. Monthly Notices of the Royal Astronomical Society. 73 (5). p.342. doi:10.1093/mnras/73.5.334. bibcode:1913MNRAS..73..334D: “[paragrapho 14, pagina 342] Taking the unit of distance R* to be that corresponding to a parallax of 1″·0 [… Annotatio:] * There is need for a name for this unit of distance. Mr. Charlier has suggested Siriometer, but if the violence to the Greek language can be overlooked, the word Astron might be adopted. Professor Turner suggests Parsec, which may be taken as an abbreviated form of ‘a distance corresponding to a parallax of one second’.”