Orion

Ori · genitive Orionis · equatorial sky

The Orion 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
203
Visible to the eye
203 stars
Brightest star
Rigel (0.13)
Best seen
December
Declination span
-9.7° to +20.3°
Nearest star
Tabit · 26.3 ly

Best from the northern hemisphere; it rises for observers between about 70°S and 80°N.

When and where to look for Orion

Orion crosses the meridian — its highest point in the sky — at local midnight around December, which makes the months from November to January the easiest time to find it in the evening. It spans declinations -9.7° to +20.3°, so best from the northern hemisphere; it rises for observers between about 70°S and 80°N.

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

Brightest stars in Orion

StarMagTypeDistance
RigelBeta Orionis0.13B8Ia860 ly
BetelgeuseAlpha Orionis0.42M2Iab700 ly
Bellatrix24Gam Ori1.64B2III252.4 ly
Alnilam46Eps Ori1.69B0Ia1,976.7 ly
Alnitak50Zet Ori1.74O9.5Ib SB736.2 ly
Saiph53Kap Ori2.07B0.5Iavar647.1 ly

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

What Orion is made of

The catalogue lists 203 stars within Orion, of which 203 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

O7
B73
A39
F20
G20
K35
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 Tabit at 26.3 light years. The most distant is 36Ups Ori at roughly 2,861 light years — stars that appear side by side here are nothing of the sort.

Deep-sky objects in Orion

  • Orion Nebula — nebula

These are marked on the sky map, so you can see where they sit relative to the constellation figure in real time.

Nearby constellations