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: 6:49  
clear_day Transit: 12:50  
SunsetSet: 18:50 south
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All Constellations » Cassiopeia » 


Altitude: 50.3°   Azimuth: 62.1°   Direction: East-North-East

HR91 is a variable and double sub-giant star in the constellation of Cassiopeia.

HR91 visual magnitude is 5.57. Because of its reltive faintness, HR91 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 HR91:


HR91 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 50.3°
Azimuth: 62.1°
Direction: East-North-East

Celestial coordinates and finder chart of HR91

HR91 is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of HR91 are provided in the following table:

00h 24m 15s
+52° 01’ 12”

The simplified sky map below shows the position of HR91 in the sky:

Finder chart HR91 star
Simplified finder chart for HR91.

Visibility of HR91 from your location

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

HR91 is circumpolar and transits at 00:09 UTC (altitude: 89.5°)

Digitized Sky Survey image of HR91

The image below is a photograph of HR91 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 HR91 is 0.013 arcsec per year in Right Ascension and -0.004 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR91 star
DSS2 image of HR91. The red arrow shows the motion of HR91 during the next 10000 years (2.17 arcmin in Right Ascension and -0.67 arcmin in declination);

Distance of HR91 from the Sun and relative movement

HR91 is distant 1,369.75 light years from the Sun and it is moving towards the Sun at the speed of 7 kilometers per second.

420.17 pc
1,369.75 ly
-7 km/s
0.013 arcsec/year
-0.004 arcsec/year

Spectral properties of HR91

HR91 belongs to spectral class B5 and has a luminosity class of IV corresponding to a sub-giant star.


The red dot in the diagram below shows where HR91 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR91. Attribution: Richard Powell / CC BY-SA

HR91 star system properties

HR91 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 HR91 double sysyem:

0.2 arcsec

Alternative designations of HR91