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🌎  Greenwich, United Kingdom [change]

η Serpentis (eta Serpentis)

η Serpentis is a variable and double hypergiant star in the constellation of Serpens.

η Serpentis visual magnitude is 3.26. Because of its moderate brightness, η Serpentis should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about η Serpentis:

η Serpentis (eta Serpentis) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 26°.

Celestial coordinates and finder chart of η Serpentis

η Serpentis 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 η Serpentis are provided in the following table:

18h 21m 18s
-02° 53’ 56”

The simplified sky map below shows the position of η Serpentis in the sky:

Finder chart η Serpentis (eta Serpentis) star
Simplified finder chart for η Serpentis (eta Serpentis).

Visibility of η Serpentis from your location

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

Today's η Serpentis (eta Serpentis) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 92.9°
Max altitude: 35.6°
Azimuth: 267.1°
η Serpentis (eta Serpentis) is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of η Serpentis

The image below is a photograph of η Serpentis 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 η Serpentis is -0.547 arcsec per year in Right Ascension and -0.7 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of η Serpentis (eta Serpentis) star
DSS2 image of η Serpentis. The red arrow shows the motion of η Serpentis during the next 1000 years (-9.12 arcmin in Right Ascension and -11.67 arcmin in declination);

Distance of η Serpentis from the Sun and relative movement

η Serpentis is distant 61.73 light years from the Sun and it is moving far from the Sun at the speed of 9 kilometers per second.

18.94 pc
61.73 ly
9 km/s
-0.547 arcsec/year
-0.7 arcsec/year

Spectral properties of η Serpentis

η Serpentis 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 η Serpentis is situated in the Hertzsprung–Russell diagram.

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

η Serpentis star system properties

η Serpentis 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 η Serpentis double sysyem:

179.7 arcsec

Alternative designations of η Serpentis

η Serpentis
(eta Serpentis)
58 Serpentis