21 Sagittarii

Below the horizon. Rise: 22:53 | Tran: 3:03 | Set: 7:09

Alt: -0.40° Az: 236.35° Direction: West-South-West

21 Sagittarii is a double bright giant star of spectral class K2 in the constellation of Sagittarius.

21 Sagittarii visual magnitude is 4.81. Because of its moderate brightness, 21 Sagittarii is easily visible to the naked eye from locations with dark skies, while it might be barely visible, or not visible at all, from light-polluted skies.

DSS2 image of 21 Sagittarii. The red arrow shows the motion of 21 Sagittarii during the next 10000 years (1.00 arcmin in Right Ascension and -4.17 arcmin in declination);

Celestial Coordinates

Apparent

Right Ascension 18h 26m 51s

Declination -20° 31’ 32”

Hour Angle 04h 10m 54s

Sidereal Time 22h 37m 45s

J2000

Right Ascension 18h 25m 20s

Declination -20° 32’ 30”

Galactic Coordinates

Galactic Longitude 11.74°

Galactic Latitude -3.75°

Finder Chart

Loading map...

Finder chart for 21 Sagittarii.

Magnitude, Color, Spectral Class

Color ⬤

Magnitude 4.81

Class Bright giant

Absolute magnitude -1.50

Spectral Type K2II

Color Index (B-V) 1.31

Temperature 4104K

The red dot in the diagram below shows where 21 Sagittarii is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of 21 Sagittarii. Attribution: Richard Powell / CC BY-SA

Star System Properties

21 Sagittarii is a visual double star which can be observed with the help of medium or large telescopes. The table below shows key information about the 21 Sagittarii double sysyem:

Main star magnitude 4.81

Secondary star magnitude 8.41

Magnitude difference 3.6

Separation 1.7 arcsec

Distance, Radial Speed, Proper Motion

21 Sagittarii is distant 597.07 light years from the Sun and it is moving towards the Sun at the speed of 12 kilometers per second.

Distance (parsec) 183.15

Distance (light year) 597.07

Radial Speed -12 km/s

Proper Motion RA 0.006 arcsec/y

Proper Motion Dec -0.025"/y

Alternative Designations

Flamsteed designation 21 Sagittarii

Henry Draper Catalogue HD169420

SAO Catalogue SAO186794

Hipparcos Catalogue HIP90289

Durchmusterung Catalogue BD-20 5134

Aitken Double Star Catalogue ADS11325

Visibility from Your Location

Today's 21 Sagittarii rise, transit and set times from Greenwich, UK are the following (all times relative to the local timezone Europe/London):

Azimuth: 110.5° RISE 22:53

Max altitude: 18.0° TRANSIT 3:03

Azimuth: 249.5° SET 7:09

Set Location

Other stars in Sagittarius