Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 4:44  
clear_day Transit: 12:57  
SunsetSet: 21:11 south
sunny DaytimeWhat's Visible Now
All Constellations » Microscopium » 


Altitude: 7.6°   Azimuth: 185.2°   Direction: South

HR7991 is a giant star in the constellation of Microscopium.

HR7991 visual magnitude is 6.35. Because of its reltive faintness, HR7991 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 HR7991:


HR7991 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 7.6°
Azimuth: 185.2°
Direction: South

Celestial coordinates and finder chart of HR7991

HR7991 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 HR7991 are provided in the following table:

20h 53m 25s
-30° 43’ 06”

The simplified sky map below shows the position of HR7991 in the sky:

Finder chart HR7991 star
Simplified finder chart for HR7991.

Visibility of HR7991 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 HR7991 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: 120.7°
Max altitude: 7.8°
Azimuth: 239.3°
HR7991 is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of HR7991

The image below is a photograph of HR7991 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 HR7991 is 0.036 arcsec per year in Right Ascension and -0.008 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR7991 star
DSS2 image of HR7991. The red arrow shows the motion of HR7991 during the next 10000 years (6.00 arcmin in Right Ascension and -1.33 arcmin in declination);

Distance of HR7991 from the Sun and relative movement

HR7991 is distant 530.94 light years from the Sun and it is moving towards the Sun at the speed of 7 kilometers per second.

162.87 pc
530.94 ly
-7 km/s
0.036 arcsec/year
-0.008 arcsec/year

Spectral properties of HR7991

HR7991 belongs to spectral class K1 and has a luminosity class of III corresponding to a giant star.


The red dot in the diagram below shows where HR7991 is situated in the Hertzsprungā€“Russell diagram.

HR Diagram
H-R diagram showing the position of HR7991. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR7991