Star Stars · In Puppis
Naos
Naos, ζ Puppis, is a blue supergiant in Puppis: the 67th brightest star in the night sky.
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- Constellation
- Puppis
- Designation
- ζ Puppis
- Apparent magnitude
- 2.21 · 67th brightest star in the night sky
- Spectral class
- O5IAf
- Distance
- 1,084 light-years
- Highest at midnight
- mid January
- Position (J2000)
- RA 08h 04m · Dec −40° 00′
A blue supergiant, around 40,000 K. About 52× brighter than the faintest star the eye can see. Gives off about 12,000 times the Sun's visible light. The light you are seeing left around 942.
When to see it
On the night of Tue 19 Jan 2027, when it is highest around midnight, on each city’s own clock:
| From | Rises | Highest | Sets |
|---|---|---|---|
| London GMT | Never rises | ||
| New York EST | 21:09 | 00:03 · 9° | 02:57 |
| Singapore GMT+8 | 19:19 | 01:13 · 49° | 07:08 |
| Sydney GMT+11 | 16:48 | 01:04 · 84° | 09:20 |
Common questions
- Can I see it from 50° north?
- No. From there it never rises: you would have to travel south of 49° north before it cleared the horizon at all.
- Can I see it from 35° south?
- Yes, and well placed: at its highest it passes almost overhead, 85° up, above most of the air’s haze.
- When is the best time of year to see it?
- Around mid January, when it stands opposite the Sun and is highest at midnight. It comes round about two hours earlier each month, so by mid April it is highest in the early evening, and in mid October not until the hours before dawn.
- How far away is it, and how bright?
- It is 1,084 light-years away, and shines at magnitude 2.21 in our sky. From that far, the Sun would be a star of magnitude 12.4: too faint for anything less than a telescope.
- Naked eye, binoculars or telescope?
- The naked eye, even from a city: at magnitude 2.21 it is brighter than the faintest stars a city sky still shows, about magnitude 4.5.
Look for
Start from Regor: Naos is 7.4° north of it, three fingers at arm’s length.
Look for
From 50° north it never rises; from 35° north it climbs to 15°; from the equator it climbs to 50°; from 35° south it climbs to 85°.
Science
Naos’s surface is about 40,000 K, some 34,200 K hotter than the Sun’s 5,772 K, so its light is strongest at about 70 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 −5.4, brighter than Sirius, the brightest star in our sky.
Did you know
Against Regor, the brighter star the hop starts from: Regor looks 1.5 times as bright as Naos in our sky; Regor is 1,117 light-years away and Naos 1,084 light-years, so side by side Regor would give off 1.6 times as much light as Naos.
Science
Naos is the 148th nearest to us of the 156 stars on these pages with a measured distance. Its nearest neighbour among them in space is Regor, about 150 light-years from it; on our sky the two are 7.4° apart.
Look for
The Sun passes 58° north of Naos around mid July, when it is highest at noon, in daylight: the weeks either side are its worst time of year. From 35° north it is above the horizon for about 7 hours a day and from 35° south about 17. It is 5° from the plane of the Milky Way, inside the band a dark sky shows.