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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: 7:48  
clear_day Transit: 11:49  
SunsetSet: 15:50 south
sleep NighttimeWhat's Visible Now?
All Constellations » Cygnus » 


Altitude: 33.9°   Azimuth: 312.7°   Direction: North-West

HR7978 is a double main-sequence star in the constellation of Cygnus.

HR7978 visual magnitude is 6.29. Because of its reltive faintness, HR7978 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 HR7978:


HR7978 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 33.9°
Azimuth: 312.7°
Direction: North-West

Celestial coordinates and finder chart of HR7978

HR7978 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 HR7978 are provided in the following table:

20h 48m 42s
+51° 54’ 38”

The simplified sky map below shows the position of HR7978 in the sky:

Finder chart HR7978 star
Simplified finder chart for HR7978.

Visibility of HR7978 from your location

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

HR7978 is circumpolar and transits at 15:48 UTC (altitude: 89.6°)

Digitized Sky Survey image of HR7978

The image below is a photograph of HR7978 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 HR7978 is 0.006 arcsec per year in Right Ascension and 0.007 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of HR7978 star
DSS2 image of HR7978. The red arrow shows the motion of HR7978 during the next 100000 years (10.00 arcmin in Right Ascension and 11.67 arcmin in declination);

Distance of HR7978 from the Sun and relative movement

HR7978 is distant 791.26 light years from the Sun and it is moving towards the Sun at the speed of 25 kilometers per second.

242.72 pc
791.26 ly
-25 km/s
0.006 arcsec/year
0.007 arcsec/year

Spectral properties of HR7978

HR7978 belongs to spectral class B8 and has a luminosity class of V corresponding to a main-sequence star.


The red dot in the diagram below shows where HR7978 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR7978. Attribution: Richard Powell / CC BY-SA

HR7978 star system properties

HR7978 is a visual double star which can be observed with the help of small or medium telescopes. The table below shows key information about the HR7978 double sysyem:

4 arcsec

Alternative designations of HR7978