Your guide to the Solar System and the night sky
🌎 Location: Greenwich, United Kingdom [change]

Altair - α Aquilae (alpha Aquilae)

Altair, also designated as α Aquilae (alpha Aquilae), is a multiple main-sequence star in the constellation of Aquila.

Altair visual magnitude is 0.77, making it the 12th brightest star in the sky. Thanks to its high brightness, Altair 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 Altair:

0.77
Main-sequence
Altair - α Aquilae (alpha Aquilae) is below the horizon from Greenwich, United Kingdom [change].

Celestial coordinates and finder chart of Altair

Altair 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 Altair are provided in the following table:

19h 50m 47s
+08° 52’ 05”
47.74°
-8.91°
Aquila

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

Finder chart Altair - α Aquilae (alpha Aquilae) star
Simplified finder chart for Altair - α Aquilae (alpha Aquilae).

Visibility of Altair from your location

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

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

Azimuth: 81.1°
Max altitude: 47.4°
Azimuth: 278.9°
Altair - α Aquilae (alpha Aquilae) is below the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of Altair

The image below is a photograph of Altair 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 Altair is 0.538 arcsec per year in Right Ascension and 0.386 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Altair - α Aquilae (alpha Aquilae) star
DSS2 image of Altair. The red arrow shows the motion of Altair during the next 1000 years (8.97 arcmin in Right Ascension and 6.43 arcmin in declination);

Distance of Altair from the Sun and relative movement

Altair is distant 16.77 light years from the Sun and it is moving towards the Sun at the speed of 26 kilometers per second.

5.14 pc
16.77 ly
-26 km/s
0.538 arcsec/year
0.386 arcsec/year

Spectral properties of Altair

Altair belongs to spectral class A7 and has a luminosity class of V corresponding to a main-sequence star.

2.21
A7V
8011K

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

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

Altair star system properties

Altair 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 Altair double sysyem:

0.77
9.37
8.6
165.2 arcsec

Alternative designations of Altair

Altair
α Aquilae
(alpha Aquilae)
SAO125122
SAO125122