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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: 6:44  
clear_day Transit: 12:10  
SunsetSet: 17:38
sunny DaytimeWhat's Visible Now?
All Constellations » Ara » 


Altitude: -49.1°   Azimuth: 252.4°   Direction: West-South-West

HR6640 is a giant star in the constellation of Ara.

HR6640 visual magnitude is 6.11. Because of its reltive faintness, HR6640 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 HR6640 is 0.009 arcsec per year in Right Ascension and -0.005 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of HR6640 star
DSS2 image of HR6640. The red arrow shows the motion of HR6640 during the next 100000 years (15.00 arcmin in Right Ascension and -8.33 arcmin in declination);

Key facts about HR6640


HR6640 is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -49.1°
Azimuth: 252.4°
Direction: West-South-West

Celestial coordinates and finder chart of HR6640

HR6640 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 HR6640 are provided in the following table:

17h 51m 44s
-45° 36’ 02”

The simplified sky map below shows the position of HR6640 in the sky:

Finder chart HR6640 star
Simplified finder chart for HR6640.

Visibility of HR6640 from your location

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

HR6640 is currently not visible from Greenwich, United Kingdom edit_location_alt

Distance of HR6640 from the Sun and relative movement

HR6640 is distant 682.01 light years from the Sun and it is moving towards the Sun at the speed of 7 kilometers per second.

209.21 pc
682.01 ly
-7 km/s
0.009 arcsec/year
-0.005 arcsec/year

Spectral properties of HR6640

HR6640 belongs to spectral class G6 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where HR6640 is situated in the HertzsprungÔÇôRussell diagram.

HR Diagram
H-R diagram showing the position of HR6640. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR6640