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A Complete Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
SunriseRise: 6:46  
clear_day Transit: 12:11  
SunsetSet: 17:36
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All Constellations » Scorpius » 


Altitude: -19.9°   Azimuth: 131.4°   Direction: South-East

HR6643 is a double giant star in the constellation of Scorpius.

HR6643 visual magnitude is 5.96. Because of its reltive faintness, HR6643 should be visible only from locations with dark skies, while it is not visible at all from skies affected by light pollution.

The proper motion of HR6643 is -0.028 arcsec per year in Right Ascension and -0.053 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR6643 star
DSS2 image of HR6643. The red arrow shows the motion of HR6643 during the next 10000 years (-4.67 arcmin in Right Ascension and -8.83 arcmin in declination);

Key facts about HR6643


HR6643 is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -19.9°
Azimuth: 131.4°
Direction: South-East

Celestial coordinates and finder chart of HR6643

HR6643 is situated south of the celestial equator, as such, it is more easily visible from the southern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of HR6643 are provided in the following table:

17h 51m 32s
-40° 46’ 21”

The simplified sky map below shows the position of HR6643 in the sky:

Finder chart HR6643 star
Simplified finder chart for HR6643.

Visibility of HR6643 from your location

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

HR6643 is currently not visible from Greenwich, United Kingdom edit_location_alt

Distance of HR6643 from the Sun and relative movement

HR6643 is distant 737.56 light years from the Sun and it is moving towards the Sun at the speed of 85 kilometers per second.

226.24 pc
737.56 ly
-85 km/s
-0.028 arcsec/year
-0.053 arcsec/year

Spectral properties of HR6643

HR6643 belongs to spectral class M2 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where HR6643 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR6643. Attribution: Richard Powell / CC BY-SA

HR6643 star system properties

HR6643 is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the HR6643 double sysyem:

23.6 arcsec

Alternative designations of HR6643