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: 4:47  
clear_day Transit: 12:56  
SunsetSet: 21:06 south
sunny DaytimeWhat's Visible Now
All Constellations » Aquarius » 


HR8121 is a variable giant star in the constellation of Aquarius.

HR8121 visual magnitude is 6.38. Because of its reltive faintness, HR8121 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 HR8121:

HR8121 is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 17°.

Celestial coordinates and finder chart of HR8121

HR8121 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 HR8121 are provided in the following table:

21h 14m 36s
+00° 05’ 31”

The simplified sky map below shows the position of HR8121 in the sky:

Finder chart HR8121 star
Simplified finder chart for HR8121.

Visibility of HR8121 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 HR8121 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: 89.9°
Max altitude: 38.6°
Azimuth: 270.1°
HR8121 is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of HR8121

The image below is a photograph of HR8121 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 HR8121 is 0.028 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 HR8121 star
DSS2 image of HR8121. The red arrow shows the motion of HR8121 during the next 10000 years (4.67 arcmin in Right Ascension and -1.50 arcmin in declination);

Distance of HR8121 from the Sun and relative movement

HR8121 is distant 684.87 light years from the Sun and it is moving towards the Sun at the speed of 124 kilometers per second.

210.08 pc
684.87 ly
-124 km/s
0.028 arcsec/year
-0.009 arcsec/year

Spectral properties of HR8121

HR8121 belongs to spectral class M1 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where HR8121 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR8121. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR8121