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A Complete Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 7:41  
clear_day Transit: 11:47  
SunsetSet: 15:53 south
sleep NighttimeWhat's Visible Now?
All Constellations » Orion » 


Altitude: 20.8°   Azimuth: 240.4°   Direction: West-South-West

HR1800 is a double star in the constellation of Orion.

HR1800 visual magnitude is 6.57. Because of its reltive faintness, HR1800 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 HR1800:


HR1800 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 20.8°
Azimuth: 240.4°
Direction: West-South-West

Celestial coordinates and finder chart of HR1800

HR1800 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 HR1800 are provided in the following table:

05h 25m 31s
-00° 32’ 39”

The simplified sky map below shows the position of HR1800 in the sky:

Finder chart HR1800 star
Simplified finder chart for HR1800.

Visibility of HR1800 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 HR1800 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: 90.5°
Max altitude: 38.0°
Azimuth: 269.5°

Digitized Sky Survey image of HR1800

The image below is a photograph of HR1800 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 HR1800 is 0.012 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.

Image of HR1800 star
DSS2 image of HR1800. The red arrow shows the motion of HR1800 during the next 10000 years (2.00 arcmin in Right Ascension and -1.17 arcmin in declination);

Distance of HR1800 from the Sun and relative movement

HR1800 is distant 737.56 light years from the Sun and it is moving towards the Sun at the speed of 9 kilometers per second.

226.24 pc
737.56 ly
-9 km/s
0.012 arcsec/year
-0.007 arcsec/year

Spectral properties of HR1800

HR1800 belongs to spectral class B9 HR1800 is also a HgSi chemically peculiar star.


The red dot in the diagram below shows where HR1800 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR1800. Attribution: Richard Powell / CC BY-SA

HR1800 star system properties

HR1800 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 HR1800 double sysyem:

0.2 arcsec

Alternative designations of HR1800