Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 6:54  
clear_day Transit: 12:49  
SunsetSet: 18:43 south
sleep NighttimeWhat's Visible Now
All Constellations » Pisces » 


Altitude: 49.5°   Azimuth: 181.9°   Direction: South

HR81 is a double hypergiant star in the constellation of Pisces.

HR81 visual magnitude is 6.56. Because of its reltive faintness, HR81 should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The table below summarizes the key facts about HR81:


HR81 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 49.5°
Azimuth: 181.9°
Direction: South

Celestial coordinates and finder chart of HR81

HR81 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 HR81 are provided in the following table:

00h 20m 54s
+10° 58’ 36”

The simplified sky map below shows the position of HR81 in the sky:

Finder chart HR81 star
Simplified finder chart for HR81.

Visibility of HR81 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 HR81 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: 79.0°
Max altitude: 49.5°
Azimuth: 281.0°

Digitized Sky Survey image of HR81

The image below is a photograph of HR81 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 HR81 is -0.046 arcsec per year in Right Ascension and -0.028 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR81 star
DSS2 image of HR81. The red arrow shows the motion of HR81 during the next 10000 years (-7.67 arcmin in Right Ascension and -4.67 arcmin in declination);

Distance of HR81 from the Sun and relative movement

HR81 is distant 624.52 light years from the Sun and it is moving towards the Sun at the speed of 18 kilometers per second.

191.57 pc
624.52 ly
-18 km/s
-0.046 arcsec/year
-0.028 arcsec/year

Spectral properties of HR81

HR81 belongs to spectral class A0 and has a luminosity class of V corresponding to a hypergiant star.


The red dot in the diagram below shows where HR81 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR81. Attribution: Richard Powell / CC BY-SA

HR81 star system properties

HR81 is a visual double star which can be observed with the help of large telescopes. The table below shows key information about the HR81 double sysyem:

0.6 arcsec

Alternative designations of HR81