在任何天球坐标系都需要定义赤道和极点。银道坐标系也一样，需要一条垂直于赤道的子午线作为银经的起点。经由国际会议决定银道坐标系的银纬和银经分别以“b”和“l”标示，银极的银纬（b）是90°（b=+90°或b=−90°）。银纬～0°的天体，就位在银河系的盘面（亦即银道面）上，也就是在银河坐标的赤道附近。
极环星系是种稀有的星系类型，它们有着几乎和银盘平面垂直，呈环形公转的大量的恒星、气体和星尘。
A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk.
万顷银波，洁白如雪，波平如镜，渺极天际。
Boundless expanse of silver wave, white as snow, wave as flat as a mirror, a very vague horizon.
本文概述了锌银蓄电池的组成、能，以及锌银蓄电池正极、极、膜技术上的进步，理论上的研究。
This paper describes the component and characteristics of silver-zinc batteries, advances in technologies of positive and negative poles and membrane, and theoretic studies.
应用推荐