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public  Greenwich, UK Greenwich, UK  ⓘ
TimezoneEurope/London
Sunrise: 5:05 
Transit: 12:56 
Sunset: 20:48
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All Constellations » Perseus » 

21 Persei

Below the horizon.  Rise: 2:49 | Tran: 12:13 | Set: 21:37
Alt: -6.22°   Az: 353.49°   Direction: North

21 Persei is a variable star of spectral class B9 in the constellation of Perseus.

21 Persei visual magnitude is 5.11. Because of its faintness, 21 Persei is visible to the naked eye only from locations with very dark skies, while it is not visible at all from skies affected by light pollution.

Image of 21 Persei star
DSS2 image of 21 Persei. The red arrow shows the motion of 21 Persei during the next 10000 years (0.50 arcmin in Right Ascension and -5.17 arcmin in declination);

Celestial Coordinates

Apparent

02h 58m 50s
+32° 02’ 05”
11h 29m 27s
14h 28m 17s

J2000

02h 57m 17s
+31° 56’ 03”

Galactic Coordinates

151.88°
-23.77°

Finder Chart

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Finder chart for 21 Persei.

Magnitude, Color, Spectral Class

5.11
21 Persei is also a Si chemically peculiar star.

-0.26
B9
10252K

The red dot in the diagram below shows where 21 Persei is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 21 Persei. Attribution: Richard Powell / CC BY-SA

Distance, Radial Speed, Proper Motion

21 Persei is distant 386.71 light years from the Sun and it is moving far from the Sun at the speed of 8 kilometers per second.

118.62
386.71
8 km/s
0.003 arcsec/y
-0.031"/y

Alternative Designations

SAO56031
SAO56031

Visibility from Your Location

Today's 21 Persei rise, transit and set times from Greenwich, UK are the following (all times relative to the local timezone Europe/London):

Azimuth: 58.0°
Max altitude: 70.6°
Azimuth: 302.0°