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public LocationGreenwich, United Kingdom
Sunrise: 4:42 
Transit: 12:59 
Sunset: 21:16
sunny   (Daytime)   What's Visible Now?

τ Persei (tau Persei)

Above the horizon.  Circumpolar today
Altitude: 62.5°   Azimuth: 290.8°   Direction: West-North-West

τ Persei is a variable and multiple giant star of spectral class G4 in the constellation of Perseus.

τ Persei visual magnitude is 3.95. Because of its moderate brightness, τ Persei is easily visible to the naked eye from locations with dark skies, while it might be barely visible, or not visible at all, from light-polluted skies.

Celestial coordinates and finder chart of τ Persei

Finder chart τ Persei (tau Persei) star
Simplified finder chart for τ Persei (tau Persei).

τ 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 τ Persei are provided in the following table:

02h 54m 15s
+52° 45’ 45”
Image of τ Persei (tau Persei) star
DSS2 image of τ Persei. The red arrow shows the motion of τ Persei during the next 100000 years (0.00 arcmin in Right Ascension and -8.33 arcmin in declination);

Key facts about τ Persei


and has a luminosity class of III corresponding to a giant star.


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

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

τ Persei star system properties

τ 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 τ Persei double sysyem:

51.7 arcsec

Distance of τ Persei from the Sun and relative movement

τ Persei is distant 247.91 light years from the Sun and it is moving far from the Sun at the speed of 2 kilometers per second.

76.05 pc
247.91 ly
2 km/s
-0.005 arcsec/year

Alternative designations of τ Persei

τ Persei
(tau Persei)

Visibility of τ Persei from your location

τ Persei (tau Persei) is circumpolar and transits at 09:13 UTC (altitude: 88.7°)