Serpens

Ser · genitive Serpentis · equatorial sky

The Serpens figure as the IAU defines it, drawn looking south with east to the left — the orientation you see standing outside.

At a glance

Catalogued stars
113
Visible to the eye
113 stars
Brightest star
Unukalhai (2.63)
Best seen
June
Declination span
-15.7° to +19.7°
Nearest star
41Gam Ser · 36.7 ly

Best from the northern hemisphere; it rises for observers between about 70°S and 74°N.

When and where to look for Serpens

Serpens crosses the meridian — its highest point in the sky — at local midnight around June, which makes the months from May to July the easiest time to find it in the evening. It spans declinations -15.7° to +19.7°, so best from the northern hemisphere; it rises for observers between about 70°S and 74°N.

The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Serpens is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.

Brightest stars in Serpens

StarMagTypeDistance
Unukalhai24Alp Ser2.63K2III74 ly
58Eta Ser3.23K0III-IV60.5 ly
32Mu Ser3.54A0V169.6 ly
55Xi Ser3.54F0IIIp105.3 ly
28Bet Ser3.65A3V155.1 ly
37Eps Ser3.71A2m70.4 ly

Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.

What Serpens is made of

The catalogue lists 113 stars within Serpens, of which 113 are magnitude 6.5 or brighter — the limit of what an unaided eye picks up under a genuinely dark sky. The rest need binoculars or a telescope.

Spectral make-up

B9
A30
F18
G16
K33
M7

Spectral class is a temperature ordering, running from O at around 30,000 K down to M below 3,500 K. A constellation is a direction, not a group, so this is simply what happens to lie along that line of sight.

The closest catalogued star in this direction is 41Gam Ser at 36.7 light years. The most distant is HD 142763 at roughly 1,599 light years — stars that appear side by side here are nothing of the sort.

Nearby constellations