Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 4:45  
clear_day Transit: 12:57  
SunsetSet: 21:10 south
wb_twilight Astronomical TwilightWhat's Visible Now
All Constellations » Perseus » 

20 Persei

Altitude: 5.2°   Azimuth: 27.6°   Direction: North-North-East

20 Persei is a variable and multiple sub-giant star in the constellation of Perseus.

20 Persei visual magnitude is 5.33. Because of its reltive faintness, 20 Persei should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The table below summarizes the key facts about 20 Persei:


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

Altitude: 5.2°
Azimuth: 27.6°
Direction: North-North-East

Celestial coordinates and finder chart of 20 Persei

20 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 20 Persei are provided in the following table:

02h 53m 42s
+38° 20’ 14”

The simplified sky map below shows the position of 20 Persei in the sky:

Finder chart 20 Persei star
Simplified finder chart for 20 Persei.

Visibility of 20 Persei from your location

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

Today's 20 Persei rise, transit and set times from Greenwich, United Kingdom edit_location_alt are the following (all times relative to the local timezone Europe/London):

Azimuth: 51.7°
Max altitude: 76.9°
Azimuth: 308.3°
20 Persei is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of 20 Persei

The image below is a photograph of 20 Persei 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 20 Persei is 0.047 arcsec per year in Right Ascension and -0.077 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of 20 Persei star
DSS2 image of 20 Persei. The red arrow shows the motion of 20 Persei during the next 10000 years (7.83 arcmin in Right Ascension and -12.83 arcmin in declination);

Distance of 20 Persei from the Sun and relative movement

20 Persei is distant 235.04 light years from the Sun and it is moving far from the Sun at the speed of 6 kilometers per second.

72.10 pc
235.04 ly
6 km/s
0.047 arcsec/year
-0.077 arcsec/year

Spectral properties of 20 Persei

20 Persei belongs to spectral class F4 and has a luminosity class of IV corresponding to a sub-giant star.


The red dot in the diagram below shows where 20 Persei is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 20 Persei. Attribution: Richard Powell / CC BY-SA

20 Persei star system properties

20 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 20 Persei double sysyem:

0.2 arcsec

Alternative designations of 20 Persei