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: 4:49  
clear_day Transit: 12:56  
SunsetSet: 21:04 south
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All Constellations » Cygnus » 


HR7721 is a main-sequence star in the constellation of Cygnus.

HR7721 visual magnitude is 6.92. Because of its reltive faintness, HR7721 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 HR7721:

HR7721 is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 85°.

Celestial coordinates and finder chart of HR7721

HR7721 is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of HR7721 are provided in the following table:

20h 12m 03s
+47° 44’ 12”

The simplified sky map below shows the position of HR7721 in the sky:

Finder chart HR7721 star
Simplified finder chart for HR7721.

Visibility of HR7721 from your location

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

HR7721 is circumpolar and transits at 03:34 UTC (altitude: 86.3°)

Digitized Sky Survey image of HR7721

The image below is a photograph of HR7721 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 HR7721 is 0.016 arcsec per year in Right Ascension and 0.004 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR7721 star
DSS2 image of HR7721. The red arrow shows the motion of HR7721 during the next 10000 years (2.67 arcmin in Right Ascension and 0.67 arcmin in declination);

Distance of HR7721 from the Sun and relative movement

HR7721 is distant 831.63 light years from the Sun and it is moving towards the Sun at the speed of 19 kilometers per second.

255.10 pc
831.63 ly
-19 km/s
0.016 arcsec/year
0.004 arcsec/year

Spectral properties of HR7721

HR7721 belongs to spectral class B7 and has a luminosity class of V corresponding to a main-sequence star.


The red dot in the diagram below shows where HR7721 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR7721. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR7721