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public LocationGreenwich, United Kingdom
Sunrise: 4:53 
Transit: 12:55 
Sunset: 20:59
sunny   (Daytime)   What's Visible Now?

τ1 Hydri (tau1 Hydri)

Altitude: -59.1°   Azimuth: 193.6°   Direction: South-South-West

τ1 Hydri is a double giant star in the constellation of Hydrus.

τ1 Hydri visual magnitude is 6.33. Because of its reltive faintness, τ1 Hydri should be visible only from locations with dark skies, while it is not visible at all from skies affected by light pollution.

The proper motion of τ1 Hydri is 0.052 arcsec per year in Right Ascension and 0.009 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of τ1 Hydri (tau1 Hydri) star
DSS2 image of τ1 Hydri. The red arrow shows the motion of τ1 Hydri during the next 10000 years (8.67 arcmin in Right Ascension and 1.50 arcmin in declination);

Key facts about τ1 Hydri


τ1 Hydri (tau1 Hydri) is below the horizon from Greenwich, United Kingdom.

Altitude: -59.1°
Azimuth: 193.6°
Direction: South-South-West

Celestial coordinates and finder chart of τ1 Hydri

τ1 Hydri is situated close to the southern celestial pole and, as such, it is easilty visible for most part of the year from the southern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of τ1 Hydri are provided in the following table:

01h 41m 21s
-79° 08’ 53”

The simplified sky map below shows the position of τ1 Hydri in the sky:

Finder chart τ1 Hydri (tau1 Hydri) star
Simplified finder chart for τ1 Hydri (tau1 Hydri).

Visibility of τ1 Hydri from your location

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

τ1 Hydri (tau1 Hydri) is currently not visible from Greenwich, United Kingdom

Distance of τ1 Hydri from the Sun and relative movement

τ1 Hydri is distant 394.67 light years from the Sun and it is moving far from the Sun at the speed of 2 kilometers per second.

121.07 pc
394.67 ly
2 km/s
0.052 arcsec/year
0.009 arcsec/year

Spectral properties of τ1 Hydri

τ1 Hydri belongs to spectral class G6 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where τ1 Hydri is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of τ1 Hydri. Attribution: Richard Powell / CC BY-SA

τ1 Hydri star system properties

τ1 Hydri 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 τ1 Hydri double sysyem:

16 arcsec

Alternative designations of τ1 Hydri

τ1 Hydri
(tau1 Hydri)