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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 » Cygnus » 


Altitude: 35.9°   Azimuth: 300.8°   Direction: West-North-West

HR7798 is a variable hypergiant star in the constellation of Cygnus.

HR7798 visual magnitude is 5.58. Because of its reltive faintness, HR7798 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 HR7798:


HR7798 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 35.9°
Azimuth: 300.8°
Direction: West-North-West

Celestial coordinates and finder chart of HR7798

HR7798 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 HR7798 are provided in the following table:

20h 22m 05s
+45° 47’ 42”

The simplified sky map below shows the position of HR7798 in the sky:

Finder chart HR7798 star
Simplified finder chart for HR7798.

Visibility of HR7798 from your location

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

HR7798 is circumpolar and transits at 15:45 UTC (altitude: 84.3°)

Digitized Sky Survey image of HR7798

The image below is a photograph of HR7798 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 HR7798 is 0.028 arcsec per year in Right Ascension and 0.044 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR7798 star
DSS2 image of HR7798. The red arrow shows the motion of HR7798 during the next 10000 years (4.67 arcmin in Right Ascension and 7.33 arcmin in declination);

Distance of HR7798 from the Sun and relative movement

HR7798 is distant 414.76 light years from the Sun and it is moving towards the Sun at the speed of 22 kilometers per second.

127.23 pc
414.76 ly
-22 km/s
0.028 arcsec/year
0.044 arcsec/year

Spectral properties of HR7798

HR7798 belongs to spectral class K0 and has a luminosity class of III corresponding to a hypergiant star.


The red dot in the diagram below shows where HR7798 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR7798. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR7798