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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
north SunriseRise: 7:40  
clear_day Transit: 11:47  
SunsetSet: 15:53 south
sleep NighttimeWhat's Visible Now?
All Constellations » Hercules » 


Altitude: -0.9°   Azimuth: 305.7°   Direction: North-West

HR6638 is a sub-giant star in the constellation of Hercules.

HR6638 visual magnitude is 5.69. Because of its reltive faintness, HR6638 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 HR6638:


HR6638 is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -0.9°
Azimuth: 305.7°
Direction: North-West

Celestial coordinates and finder chart of HR6638

HR6638 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 HR6638 are provided in the following table:

17h 48m 24s
+20° 33’ 56”

The simplified sky map below shows the position of HR6638 in the sky:

Finder chart HR6638 star
Simplified finder chart for HR6638.

Visibility of HR6638 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 HR6638 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: 69.4°
Max altitude: 59.1°
Azimuth: 290.6°

Digitized Sky Survey image of HR6638

The image below is a photograph of HR6638 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 HR6638 is 0.026 arcsec per year in Right Ascension and 0.008 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR6638 star
DSS2 image of HR6638. The red arrow shows the motion of HR6638 during the next 10000 years (4.33 arcmin in Right Ascension and 1.33 arcmin in declination);

Distance of HR6638 from the Sun and relative movement

HR6638 is distant 250.00 light years from the Sun and it is moving towards the Sun at the speed of 26 kilometers per second.

76.69 pc
250.00 ly
-26 km/s
0.026 arcsec/year
0.008 arcsec/year

Spectral properties of HR6638

HR6638 belongs to spectral class G5 and has a luminosity class of IV corresponding to a sub-giant star.


The red dot in the diagram below shows where HR6638 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR6638. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR6638