73 Ophiuchi

Below the horizon. Rise: 6:41 | Tran: 12:59 | Set: 19:17

Alt: -27.54° Az: 38.62° Direction: North-East

73 Ophiuchi is a variable and multiple main-sequence star of spectral class F2 in the constellation of Ophiuchus.

73 Ophiuchi visual magnitude is 5.73. Because of its faintness, 73 Ophiuchi is visible to the naked eye only from locations with very dark skies, while it is not visible at all from skies affected by light pollution.

DSS2 image of 73 Ophiuchi. The red arrow shows the motion of 73 Ophiuchi during the next 10000 years (6.33 arcmin in Right Ascension and -1.17 arcmin in declination);

Celestial Coordinates

Apparent

Right Ascension 18h 10m 48s

Declination +03° 59’ 58”

Hour Angle 14h 14m 46s

Sidereal Time 08h 25m 34s

J2000

Right Ascension 18h 09m 33s

Declination +03° 59’ 35”

Galactic Coordinates

Galactic Longitude 31.72°

Galactic Latitude 11.13°

Finder Chart

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Finder chart for 73 Ophiuchi.

Magnitude, Color, Spectral Class

Color ⬤

Magnitude 5.73

Class Main-sequence

Absolute magnitude 2.19

Spectral Type F2V

Color Index (B-V) 0.37

Temperature 7044K

The red dot in the diagram below shows where 73 Ophiuchi is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of 73 Ophiuchi. Attribution: Richard Powell / CC BY-SA

Star System Properties

73 Ophiuchi 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 73 Ophiuchi double sysyem:

Main star magnitude 5.73

Secondary star magnitude 6.93

Magnitude difference 1.2

Separation 0.3 arcsec

Distance, Radial Speed, Proper Motion

73 Ophiuchi is distant 166.16 light years from the Sun and it is moving towards the Sun at the speed of 17 kilometers per second.

Distance (parsec) 50.97

Distance (light year) 166.16

Radial Speed -17 km/s

Proper Motion RA 0.038 arcsec/y

Proper Motion Dec -0.007"/y

Alternative Designations

Flamsteed designation 73 Ophiuchi

Henry Draper Catalogue HD166233

SAO Catalogue SAO123187

Hipparcos Catalogue HIP88964

Durchmusterung Catalogue BD+03 3610

General Catalogue of Variable Stars 10287

Aitken Double Star Catalogue ADS11111

Visibility from Your Location

Today's 73 Ophiuchi rise, transit and set times from Greenwich, UK are the following (all times relative to the local timezone Europe/London):

Azimuth: 86.0° RISE 6:41

Max altitude: 42.5° TRANSIT 12:59

Azimuth: 274.0° SET 19:17

Set Location

Other stars in Ophiuchus