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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: 6:52  
clear_day Transit: 12:11  
SunsetSet: 17:31
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All Constellations » Andromeda » 

τ Andromedae (tau Andromedae)

Altitude: 18.4°   Azimuth: 47.0°   Direction: North-East

τ Andromedae is a variable and double giant star in the constellation of Andromeda.

τ Andromedae visual magnitude is 4.94. Because of its moderate brightness, τ Andromedae should be easily visible from locations with dark skies, while it can be barely visible, or not visible at all, from skies affected by light pollution.

The proper motion of τ Andromedae is 0.013 arcsec per year in Right Ascension and -0.025 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of τ Andromedae (tau Andromedae) star
DSS2 image of τ Andromedae. The red arrow shows the motion of τ Andromedae during the next 10000 years (2.17 arcmin in Right Ascension and -4.17 arcmin in declination);

Key facts about τ Andromedae


τ Andromedae (tau Andromedae) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 18.4°
Azimuth: 47.0°
Direction: North-East

Celestial coordinates and finder chart of τ Andromedae

τ Andromedae 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 Andromedae are provided in the following table:

01h 40m 34s
+40° 34’ 36”

The simplified sky map below shows the position of τ Andromedae in the sky:

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

Visibility of τ Andromedae from your location

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

τ Andromedae (tau Andromedae) is circumpolar and transits at 15:16 UTC (altitude: 79.1°)

Distance of τ Andromedae from the Sun and relative movement

τ Andromedae is distant 680.58 light years from the Sun and it is moving towards the Sun at the speed of 14 kilometers per second.

208.77 pc
680.58 ly
-14 km/s
0.013 arcsec/year
-0.025 arcsec/year

Spectral properties of τ Andromedae

τ Andromedae belongs to spectral class B8 and has a luminosity class of III corresponding to a giant star.


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

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

τ Andromedae star system properties

τ Andromedae is a visual double star which can be observed with the help of small or medium telescopes. The table below shows key information about the τ Andromedae double sysyem:

52.3 arcsec

Alternative designations of τ Andromedae

τ Andromedae
(tau Andromedae)
53 Andromedae