τ1 Hydrae (tau1 Hydrae)

Altitude: -37.0° Azimuth: 31.7° Direction: North-North-East

τ1 Hydrae is a double main-sequence star in the constellation of Hydra.

τ1 Hydrae visual magnitude is 4.6. Because of its moderate brightness, τ1 Hydrae should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about τ1 Hydrae:

Color of τ1 Hydrae ⬤

Magnitude of τ1 Hydrae 4.6

Class Main-sequence

VISIBILITY RIGHT NOW

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

Altitude: -37.0°
Azimuth: 31.7°
Direction: North-North-East

Celestial coordinates and finder chart of τ1 Hydrae

τ1 Hydrae is situated close to the celestial equator, as such, it is at least partly visible from both hemispheres in certain times of the year. Celestial coordinates for the J2000 equinox as well as galactic coordinates of τ1 Hydrae are provided in the following table:

Right Ascension J2000 09h 29m 08s

Declination J2000 -02° 46’ 08”

Galactic Longitude 236.23°

Galactic Latitude 32.86°

Constellation Hydra

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

Finder chart τ1 Hydrae (tau1 Hydrae) star

Simplified finder chart for τ1 Hydrae (tau1 Hydrae).

Visibility of τ1 Hydrae 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 τ1 Hydrae (tau1 Hydrae) 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: 92.8° RISE 4:29

Max altitude: 35.8° TRANSIT 10:13

Azimuth: 267.2° SET 15:57

Digitized Sky Survey image of τ1 Hydrae

The image below is a photograph of τ1 Hydrae 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 τ1 Hydrae is 0.13 arcsec per year in Right Ascension and -0.015 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

DSS2 image of τ1 Hydrae. The red arrow shows the motion of τ1 Hydrae during the next 1000 years (2.17 arcmin in Right Ascension and -0.25 arcmin in declination);

Distance of τ1 Hydrae from the Sun and relative movement

τ1 Hydrae is distant 55.75 light years from the Sun and it is moving far from the Sun at the speed of 10 kilometers per second.

Distance (parsec) 17.10 pc

Distance (light year) 55.75 ly

Heliocentric radial velocity 10 km/s

Proper Motion RA 0.13 arcsec/year

Proper Motion Dec -0.015 arcsec/year

Spectral properties of τ1 Hydrae

τ1 Hydrae belongs to spectral class F6 and has a luminosity class of V corresponding to a main-sequence star.

Absolute magnitude 3.44

Spectral Type F6V

Color Index (B-V) 0.46

Temperature of τ1 Hydrae 6576K

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

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

τ1 Hydrae star system properties

τ1 Hydrae is a visual double star which can be observed with binoculars or small telescopes. The table below shows key information about the τ1 Hydrae double sysyem:

Main star magnitude 4.6

Secondary star magnitude 7.6

Magnitude difference 3

Separation 65.7 arcsec

Alternative designations of τ1 Hydrae

Bayer designation τ1 Hydrae
(tau1 Hydrae)

Flamsteed designation 31 Hydrae

Henry Draper Catalogue HD81997

SAO Catalogue SAO136895

Hipparcos Catalogue HIP46509

Durchmusterung Catalogue BD-02 2901

Gliese Catalogue Gl 348 A

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