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A Complete Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
SunriseRise: 6:59  
clear_day Transit: 12:12  
SunsetSet: 17:25
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All Constellations » Perseus » 

9 Persei

Altitude: 17.3°   Azimuth: 0.3°   Direction: North

9 Persei is a variable and double supergiant star in the constellation of Perseus.

9 Persei visual magnitude is 5.17. Because of its reltive faintness, 9 Persei should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The proper motion of 9 Persei is -0.002 arcsec per year in Right Ascension and -0.002 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of 9 Persei star
DSS2 image of 9 Persei. The red arrow shows the motion of 9 Persei during the next 100000 years (-3.33 arcmin in Right Ascension and -3.33 arcmin in declination);

Key facts about 9 Persei


9 Persei is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 17.3°
Azimuth: 0.3°
Direction: North

Celestial coordinates and finder chart of 9 Persei

9 Persei is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of 9 Persei are provided in the following table:

02h 22m 21s
+55° 50’ 44”

The simplified sky map below shows the position of 9 Persei in the sky:

Finder chart 9 Persei star
Simplified finder chart for 9 Persei.

Visibility of 9 Persei from your location

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

9 Persei is circumpolar and transits at 16:10 UTC (altitude: 85.6°)

Distance of 9 Persei from the Sun and relative movement

9 Persei is distant 2,050.31 light years from the Sun and it is moving towards the Sun at the speed of 15 kilometers per second.

628.93 pc
2,050.31 ly
-15 km/s
-0.002 arcsec/year
-0.002 arcsec/year

Spectral properties of 9 Persei

9 Persei belongs to spectral class A2 and has a luminosity class of I corresponding to a supergiant star.


The red dot in the diagram below shows where 9 Persei is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 9 Persei. Attribution: Richard Powell / CC BY-SA

9 Persei star system properties

9 Persei 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 9 Persei double sysyem:

11.6 arcsec

Alternative designations of 9 Persei