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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: 7:40  
clear_day Transit: 11:47  
SunsetSet: 15:53 south
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All Constellations » Aquarius » 

Sadalmelik - α Aquarii (alpha Aquarii)

Altitude: 24.3°   Azimuth: 234.8°   Direction: South-West

Sadalmelik, also designated as α Aquarii (alpha Aquarii), is a double supergiant star in the constellation of Aquarius.

Sadalmelik visual magnitude is 2.96. Thanks to its high brightness, Sadalmelik is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Sadalmelik:


Sadalmelik - α Aquarii (alpha Aquarii) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 24.3°
Azimuth: 234.8°
Direction: South-West

Celestial coordinates and finder chart of Sadalmelik

Sadalmelik 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 Sadalmelik are provided in the following table:

22h 05m 47s
-00° 19’ 10”

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

Finder chart Sadalmelik - α Aquarii (alpha Aquarii) star
Simplified finder chart for Sadalmelik - α Aquarii (alpha Aquarii).

Visibility of Sadalmelik 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 Sadalmelik - α Aquarii (alpha Aquarii) 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: 90.3°
Max altitude: 38.2°
Azimuth: 269.7°

Digitized Sky Survey image of Sadalmelik

The image below is a photograph of Sadalmelik 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 Sadalmelik is 0.02 arcsec per year in Right Ascension and -0.01 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Sadalmelik - α Aquarii (alpha Aquarii) star
DSS2 image of Sadalmelik. The red arrow shows the motion of Sadalmelik during the next 10000 years (3.33 arcmin in Right Ascension and -1.67 arcmin in declination);

Distance of Sadalmelik from the Sun and relative movement

Sadalmelik is distant 758.14 light years from the Sun and it is moving far from the Sun at the speed of 8 kilometers per second.

232.56 pc
758.14 ly
8 km/s
0.02 arcsec/year
-0.01 arcsec/year

Spectral properties of Sadalmelik

Sadalmelik belongs to spectral class G2 and has a luminosity class of I corresponding to a supergiant star.


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

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

Sadalmelik star system properties

Sadalmelik 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 Sadalmelik double sysyem:

113 arcsec

Alternative designations of Sadalmelik

α Aquarii
(alpha Aquarii)