SkyRef / Stars

Segin

ε Cas. Magnitude 3.38, blue-white. Visible to the naked eye from a reasonably dark site.

The numbers

Designationε Cas
Magnitude3.38
Colourblue-white
Right ascension1.907h
Declination+63.67°
B−V index-0.15
CatalogueHR 542

What you are looking at

Astronomers call it ε Cas — the Bayer designation, which reads as a Greek letter ranking its brightness within its constellation. Segin is the name people actually use.

Segin shines at magnitude 3.38, making it visible to the naked eye from a reasonably dark site. Its B−V colour index of -0.15 makes it blue-white to the eye, corresponding to a surface temperature of over 10,000 K.

It sits at right ascension 1.91 hours and declination +63.7°. It is circumpolar from most of the northern hemisphere, meaning it never sets and can be found on any clear night.

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