# 子午圈

（重定向自上子午圈

## 曲率半径

${\displaystyle M={\frac {a(1-e^{2})}{(1-e^{2}{\sin }^{2}B)^{\frac {3}{2}}}}}$

${\displaystyle B}$ ${\displaystyle N/{\text{m}}}$ ${\displaystyle M/{\text{m}}}$
${\displaystyle 0^{\circ }}$ ${\displaystyle 6\,378\,245}$ ${\displaystyle 6\,335\,553}$
${\displaystyle 15^{\circ }}$ ${\displaystyle 6\,379\,675}$ ${\displaystyle 6\,339\,816}$
${\displaystyle 30^{\circ }}$ ${\displaystyle 6\,383\,588}$ ${\displaystyle 6\,351\,488}$
${\displaystyle 45^{\circ }}$ ${\displaystyle 6\,388\,954}$ ${\displaystyle 6\,367\,491}$
${\displaystyle 60^{\circ }}$ ${\displaystyle 6\,394\,315}$ ${\displaystyle 6\,383\,561}$
${\displaystyle 75^{\circ }}$ ${\displaystyle 6\,398\,255}$ ${\displaystyle 6\,395\,368}$
${\displaystyle 90^{\circ }}$ ${\displaystyle 6\,399\,699}$ ${\displaystyle 6\,399\,699}$

## 參考資料

• Millar, William (2006). The Amateur Astronomer's Introduction to the Celestial Sphere. Cambridge University Press.
• 《簡明天文學詞典》P.42，上海辭書出版社1986年12月初版，書號：13187.4
• 《天文學名詞1998》P.7, 10科學出版社2001年2月初版，ISBN 7-03-007140-9
1. ^ 孔祥元; 郭际明; 刘宗泉. 大地测量学基础. 武汉大学出版社. 2001: 64–78. ISBN 978-7-30-707562-7.