73 Ophiuchi

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

73 Ophiuchi visual magnitude is 5.73. Because of its reltive faintness, 73 Ophiuchi 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 73 Ophiuchi:

Color of 73 Ophiuchi ⬤

Magnitude of 73 Ophiuchi 5.73

Class Main-sequence

VISIBILITY RIGHT NOW 73 Ophiuchi is above the horizon from Greenwich, United Kingdom [change]. Altitude: 34°.

Celestial coordinates and finder chart of 73 Ophiuchi

73 Ophiuchi 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 73 Ophiuchi are provided in the following table:

Right Ascension J2000 18h 09m 33s

Declination J2000 +03° 59’ 35”

Galactic Longitude 31.72°

Galactic Latitude 11.13°

Constellation Ophiuchus

The simplified sky map below shows the position of 73 Ophiuchi in the sky:

Simplified finder chart for 73 Ophiuchi.

Visibility of 73 Ophiuchi from your location

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

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

Azimuth: 86.0° RISE 0:10

Max altitude: 42.5° TRANSIT 6:32

Azimuth: 274.0° SET 12:50

RIGHT NOW 73 Ophiuchi is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of 73 Ophiuchi

The image below is a photograph of 73 Ophiuchi 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 73 Ophiuchi is 0.038 arcsec per year in Right Ascension and -0.007 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

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);

Distance of 73 Ophiuchi from the Sun and relative movement

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 pc

Distance (light year) 166.16 ly

Heliocentric radial velocity -17 km/s

Proper Motion RA 0.038 arcsec/year

Proper Motion Dec -0.007 arcsec/year

Spectral properties of 73 Ophiuchi

73 Ophiuchi belongs to spectral class F2 and has a luminosity class of V corresponding to a main-sequence star.

Absolute magnitude 2.19

Spectral Type F2V

Color Index (B-V) 0.37

Temperature of 73 Ophiuchi 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

73 Ophiuchi 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

Alternative designations of 73 Ophiuchi

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

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Other stars in Ophiuchus