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public LocationGreenwich, UK
Sunrise: 5:15 
Transit: 13:06 
Sunset: 20:56
wb_twilight   (Nautical Twilight)   What's Visible Now?
All Constellations » Eridanus » 

τ4 Eridani (tau4 Eridani)

Above the horizon.  Rise: 4:07 | Tran: 8:06 | Set: 12:05
Alt: 2.95°   Az: 131.18°   Direction: South-East

τ4 Eridani is a variable and multiple giant star of spectral class M3 in the constellation of Eridanus.

τ4 Eridani visual magnitude is 3.69. Because of its moderate brightness, τ4 Eridani 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.

Image of τ4 Eridani (tau4 Eridani) star
DSS2 image of τ4 Eridani. The red arrow shows the motion of τ4 Eridani during the next 10000 years (8.67 arcmin in Right Ascension and 5.50 arcmin in declination);

Celestial Coordinates


03h 20m 36s
-21° 40’ 11”
20h 24m 05s
23h 44m 41s


03h 19m 31s
-21° 45’ 28”

Galactic Coordinates


Finder Chart

Finder chart τ4 Eridani (tau4 Eridani) star
Simplified finder chart for τ4 Eridani (tau4 Eridani).

Magnitude, Color, Spectral Class



The red dot in the diagram below shows where τ4 Eridani is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of τ4 Eridani. Attribution: Richard Powell / CC BY-SA

Star System Properties

τ4 Eridani 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 τ4 Eridani double sysyem:

5.5 arcsec

Distance, Radial Speed, Proper Motion

τ4 Eridani is distant 258.12 light years from the Sun and it is moving far from the Sun at the speed of 42 kilometers per second.

42 km/s
0.052 arcsec/y

Alternative Designations

τ4 Eridani
(tau4 Eridani)

Visibility from Your Location

Today's τ4 Eridani (tau4 Eridani) rise, transit and set times from Greenwich, UK are the following (all times relative to the local timezone Europe/London):

Azimuth: 111.7°
Max altitude: 16.9°
Azimuth: 248.3°