North polar sequence explained

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 Today it has been replaced by the UBV photometric system.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

• Photometric system
• Stellar classification

References

1. Web site: North Polar Sequence - Oxford Reference.
2. Web site: eSky: North Polar Sequence. www.glyphweb.com.

Further reading

• Book: C.R. Kitchin. Astrophysical Techniques, Fourth Edition. 2003. Taylor & Francis. 978-1-4200-5702-7. 446.

External links

• Schematic images