Star Stars · In Orion
Hatysa
Hatysa, ι Orionis, is a blue giant in Orion: the 124th brightest star in the night sky.
Save the chart (SVG) Tactile chart (A4 SVG)
- Constellation
- Orion
- Designation
- ι Orionis
- Apparent magnitude
- 2.75 · 124th brightest star in the night sky
- Spectral class
- O9III
- Distance
- 2,330 light-years
- Highest at midnight
- mid December
- Position (J2000)
- RA 05h 35m · Dec −05° 55′
A blue giant, around 32,000 K. About 32× brighter than the faintest star the eye can see. Gives off about 34,000 times the Sun's visible light. The light you are seeing left around 305 BC.
When to see it
On the night of Sat 12 Dec 2026, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | 18:41 | 00:10 · 33° | 05:39 |
| New York EST | 18:26 | 00:05 · 43° | 05:43 |
| Singapore GMT+8 | 19:17 | 01:15 · 83° | 07:14 |
| Sydney GMT+11 | 18:51 | 01:06 · 62° | 07:21 |
Common questions
- Can I see it from 50° north?
- Yes. It rises and sets, and at its highest it stands 34° up in the south.
- Can I see it from 35° south?
- Yes. It rises and sets, and at its highest it stands 61° up in the north.
- When is the best time of year to see it?
- Around mid December, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid March it is highest in the early evening, and in mid September not until the hours before dawn.
- How far away is it, and how bright?
- It is 2,330 light-years away, and shines at magnitude 2.75 in our sky. From that far, the Sun would be a star of magnitude 14.1: too faint for anything less than a telescope.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.75 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Alnitak: Hatysa is 4.2° south of it, three fingers at arm’s length.
Look for
From 50° north it climbs to 34°; from 35° north it climbs to 49°; from the equator it climbs to 84°; from 35° south it climbs to 61°.
Science
Hatysa’s surface is about 32,000 K, some 26,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 90 nm, in the ultraviolet, past the violet end of what the eye can see, where the Sun’s is strongest at 500 nm. Moved to 33 light-years, the distance astronomers compare stars at, it would shine at magnitude −6.5, brighter than Sirius, the brightest star in our sky.
Did you know
Against Alnitak, the brighter star the hop starts from: Alnitak looks 2.5 times as bright as Hatysa in our sky, but Alnitak is 736 light-years away and Hatysa 2,330 light-years, so side by side Hatysa would give off 3.9 times as much light as Alnitak.
Science
Hatysa is the farthest from us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Alnilam, about 390 light-years from it; on our sky the two are 4.7° apart.
Look for
The Sun passes 29° north of Hatysa around mid June, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 50° north it is above the horizon for about 11 hours a day, from 35° north about 11 and from 35° south about 13. It is 20° from the plane of the Milky Way.