Your guide to the Solar System and the night sky
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🌎  Observing from: Greenwich, United Kingdom [change]
🌅 Sunrise: 5:57  ☀️ Transit: 12:05  🌅 Sunset: 18:14

Alderamin - α Cephei (alpha Cephei)

Alderamin, also designated as α Cephei (alpha Cephei), is a variable and multiple main-sequence star in the constellation of Cepheus.

Alderamin visual magnitude is 2.44, making it the 86th brightest star in the sky. Thanks to its high brightness, Alderamin is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Alderamin:

Alderamin - α Cephei (alpha Cephei) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 50°.

Celestial coordinates and finder chart of Alderamin

Alderamin is situated close to the northern celestial pole and, as such, it is visible for most part of the year from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Alderamin are provided in the following table:

21h 18m 34s
+62° 35’ 08”

The simplified sky map below shows the position of Alderamin in the sky:

Finder chart Alderamin - α Cephei (alpha Cephei) star
Simplified finder chart for Alderamin - α Cephei (alpha Cephei).

Visibility of Alderamin from your location

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Alderamin - α Cephei (alpha Cephei) is circumpolar and transits at 09:16 UTC (altitude: 78.9°)

Digitized Sky Survey image of Alderamin

The image below is a photograph of Alderamin from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of Alderamin is 0.151 arcsec per year in Right Ascension and 0.049 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Alderamin - α Cephei (alpha Cephei) star
DSS2 image of Alderamin. The red arrow shows the motion of Alderamin during the next 1000 years (2.52 arcmin in Right Ascension and 0.82 arcmin in declination);

Distance of Alderamin from the Sun and relative movement

Alderamin is distant 48.77 light years from the Sun and it is moving towards the Sun at the speed of 10 kilometers per second.

14.96 pc
48.77 ly
-10 km/s
0.151 arcsec/year
0.049 arcsec/year

Spectral properties of Alderamin

Alderamin belongs to spectral class A7 and has a luminosity class of V corresponding to a main-sequence star.


The red dot in the diagram below shows where Alderamin is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of Alderamin. Attribution: Richard Powell / CC BY-SA

Alderamin star system properties

Alderamin is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the Alderamin double sysyem:

206.8 arcsec

Alternative designations of Alderamin

α Cephei
(alpha Cephei)