Your Guide to the Solar System and the Night Sky
This site is free and ad-free thanks to the support of our users. If you can, please consider a donation.
public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 6:44  
clear_day Transit: 12:51  
SunsetSet: 18:57 south
sunny DaytimeWhat's Visible Now
All Constellations » Aquarius » 

τ2 Aquarii (tau2 Aquarii)

Altitude: -49.6°   Azimuth: 26.8°   Direction: North-North-East

τ2 Aquarii is a variable and double hypergiant star in the constellation of Aquarius.

τ2 Aquarii visual magnitude is 4.01. Because of its moderate brightness, τ2 Aquarii 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 τ2 Aquarii:


τ2 Aquarii (tau2 Aquarii) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -49.6°
Azimuth: 26.8°
Direction: North-North-East

Celestial coordinates and finder chart of τ2 Aquarii

τ2 Aquarii 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 τ2 Aquarii are provided in the following table:

22h 49m 35s
-13° 35’ 32”

The simplified sky map below shows the position of τ2 Aquarii in the sky:

Finder chart τ2 Aquarii (tau2 Aquarii) star
Simplified finder chart for τ2 Aquarii (tau2 Aquarii).

Visibility of τ2 Aquarii 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 τ2 Aquarii (tau2 Aquarii) 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: 103.6°
Max altitude: 24.9°
Azimuth: 256.4°

Digitized Sky Survey image of τ2 Aquarii

The image below is a photograph of τ2 Aquarii 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 τ2 Aquarii is -0.012 arcsec per year in Right Ascension and -0.038 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of τ2 Aquarii (tau2 Aquarii) star
DSS2 image of τ2 Aquarii. The red arrow shows the motion of τ2 Aquarii during the next 10000 years (-2.00 arcmin in Right Ascension and -6.33 arcmin in declination);

Distance of τ2 Aquarii from the Sun and relative movement

τ2 Aquarii is distant 379.95 light years from the Sun and it is moving far from the Sun at the speed of 1 kilometers per second.

116.55 pc
379.95 ly
1 km/s
-0.012 arcsec/year
-0.038 arcsec/year

Spectral properties of τ2 Aquarii

τ2 Aquarii belongs to spectral class M0 and has a luminosity class of III corresponding to a hypergiant star.


The red dot in the diagram below shows where τ2 Aquarii is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of τ2 Aquarii. Attribution: Richard Powell / CC BY-SA

τ2 Aquarii star system properties

τ2 Aquarii 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 τ2 Aquarii double sysyem:

132.5 arcsec

Alternative designations of τ2 Aquarii

τ2 Aquarii
(tau2 Aquarii)