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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: 7:47  
clear_day Transit: 11:49  
SunsetSet: 15:50 south
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All Constellations » Serpens » 

Alya - θ1 Serpentis (theta1 Serpentis)

Altitude: 17.5°   Azimuth: 105.9°   Direction: East-South-East

Alya, also designated as θ1 Serpentis (theta1 Serpentis), is a variable and multiple main-sequence star in the constellation of Serpens.

Alya visual magnitude is 4.62. Because of its moderate brightness, Alya should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about Alya:


Alya - θ1 Serpentis (theta1 Serpentis) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 17.5°
Azimuth: 105.9°
Direction: East-South-East

Celestial coordinates and finder chart of Alya

Alya 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 Alya are provided in the following table:

18h 56m 13s
+04° 12’ 12”

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

Finder chart Alya - θ1 Serpentis (theta1 Serpentis) star
Simplified finder chart for Alya - θ1 Serpentis (theta1 Serpentis).

Visibility of Alya 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 Alya - θ1 Serpentis (theta1 Serpentis) 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: 85.8°
Max altitude: 42.7°
Azimuth: 274.2°

Digitized Sky Survey image of Alya

The image below is a photograph of Alya 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 Alya is 0.049 arcsec per year in Right Ascension and 0.031 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of Alya - θ1 Serpentis (theta1 Serpentis) star
DSS2 image of Alya. The red arrow shows the motion of Alya during the next 10000 years (8.17 arcmin in Right Ascension and 5.17 arcmin in declination);

Distance of Alya from the Sun and relative movement

Alya is distant 131.82 light years from the Sun and it is moving towards the Sun at the speed of 46 kilometers per second.

40.44 pc
131.82 ly
-46 km/s
0.049 arcsec/year
0.031 arcsec/year

Spectral properties of Alya

Alya belongs to spectral class A5 and has a luminosity class of V corresponding to a main-sequence star.


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

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

Alya star system properties

Alya is a visual double star which can be observed with binoculars or small telescopes. The table below shows key information about the Alya double sysyem:

22.2 arcsec

Alternative designations of Alya

θ1 Serpentis
(theta1 Serpentis)
63 Serpentis