| 词条 | North polar sequence |
| 释义 |
The North polar sequence is a group of 96 stars that was used to define stellar magnitudes and colors.[1] The cluster of stars lies within two degrees of the Northern Celestial pole.[1] That fact makes them visible to everyone in the northern hemisphere.[2] Originally proposed by Edward Charles Pickering, the system was used between 1900 and 1950. Today it has been replaced by the UBV photometric system. See also
References1. ^1 {{cite web|url=http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100239512|title=North Polar Sequence - Oxford Reference|publisher=}} 2. ^{{cite web|url=http://www.glyphweb.com/esky/concepts/northpolarsequence.html|title=eSky: North Polar Sequence|website=www.glyphweb.com}} External links
1 : Photometric systems |
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