η Sagittarii (eta Sagittarii)

Altitude: -73.5° Azimuth: 31.3° Direction: North-North-East

η Sagittarii is a variable and multiple giant star in the constellation of Sagittarius.

η Sagittarii visual magnitude is 3.11. Because of its moderate brightness, η Sagittarii 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 Sagittarii:

Color of η Sagittarii ⬤

Magnitude of η Sagittarii 3.11

Class Giant

VISIBILITY RIGHT NOW

η Sagittarii (eta Sagittarii) is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -73.5°
Azimuth: 31.3°
Direction: North-North-East

Celestial coordinates and finder chart of η Sagittarii

η Sagittarii 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 η Sagittarii are provided in the following table:

Right Ascension J2000 18h 17m 37s

Declination J2000 -36° 45’ 42”

Galactic Longitude 356.44°

Galactic Latitude -9.68°

Constellation Sagittarius

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

Finder chart η Sagittarii (eta Sagittarii) star

Simplified finder chart for η Sagittarii (eta Sagittarii).

Visibility of η Sagittarii 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 η Sagittarii (eta Sagittarii) 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: 126.8° RISE 12:12

Max altitude: 1.8° TRANSIT 13:33

Azimuth: 233.2° SET 14:53

Digitized Sky Survey image of η Sagittarii

The image below is a photograph of η Sagittarii 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 Sagittarii is -0.128 arcsec per year in Right Ascension and -0.167 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of η Sagittarii (eta Sagittarii) star

DSS2 image of η Sagittarii. The red arrow shows the motion of η Sagittarii during the next 1000 years (-2.13 arcmin in Right Ascension and -2.78 arcmin in declination);

Distance of η Sagittarii from the Sun and relative movement

η Sagittarii is distant 149.06 light years from the Sun and it is moving far from the Sun at the speed of 1 kilometers per second.

Distance (parsec) 45.72 pc

Distance (light year) 149.06 ly

Heliocentric radial velocity 1 km/s

Proper Motion RA -0.128 arcsec/year

Proper Motion Dec -0.167 arcsec/year

Spectral properties of η Sagittarii

η Sagittarii belongs to spectral class M3 and has a luminosity class of III corresponding to a giant star.

Absolute magnitude -0.19

Spectral Type M3III

Color Index (B-V) 1.56

Temperature of η Sagittarii 3705K

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

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

η Sagittarii star system properties

η Sagittarii 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 η Sagittarii double sysyem:

Main star magnitude 3.11

Secondary star magnitude 8.01

Magnitude difference 4.9

Separation 3.5 arcsec

Alternative designations of η Sagittarii

Bayer designation η Sagittarii
(eta Sagittarii)

Henry Draper Catalogue HD167618

SAO Catalogue SAO209957

Hipparcos Catalogue HIP89642

Durchmusterung Catalogue CD-3612423

FK5 Catalogue 683

General Catalogue of Variable Stars Eta Sgr

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