Puppis (The Stern) & M46/M47 Sky Guide
Puppis IAU constellation (673 sq deg, rank 20): February Milky Way stern of Argo Navis with Naos (+2.21) and open clusters M46, M47, and M93.
Sky Navigation & Astrophysical Context
Covering 673 square degrees east and south of Canis Major, Puppis is the largest of the three modern constellations (alongside Carina and Vela) created when Nicolas-Louis de Lacaille subdivided the immense classical ship Argo Navis in 1756, and ranks twentieth in area among all 88 IAU constellations. Because the three divisions share a single original sequence of Bayer Greek letters, Puppis has no Alpha, Beta, Gamma, Delta, or Epsilon stars (which belong to Carina and Vela); instead, its brightest stars begin at Zeta, Pi, Rho, Tau, and Sigma Puppis.
Its luminary is Naos (Zeta Puppis, V = +2.21), one of the closest and visually brightest O-type supergiants in the entire sky (spectral class O4 If(n)p at ~330 parsecs): with a surface temperature of ~40,000 K and a bolometric luminosity exceeding 500,000 suns, Naos sheds mass via a fierce stellar wind at 2,500 km/s. Nearby Pi Puppis (+2.71) sits at the center of the sparkling binocular open cluster Collinder 135, while L² Puppis is an AGB red giant at 64 parsecs with an ALMA-resolved circumstellar disk.
Northern Puppis, easily accessible from mid-northern latitudes just east of Sirius, hosts three Messier open clusters: the dramatic binocular duo Messier 47 (bright, coarse, naked-eye visible at +4.2) and Messier 46 (a rich 500-star carpet at +6.1 with the foreground planetary nebula NGC 2438 superimposed on its northern face), plus the arrowhead-shaped cluster Messier 93 near Xi Puppis (Asmidiske) and the bipolar protoplanetary Calabash ('Rotten Egg') Nebula (OH 231.8+4.2).
Equatorial Center Position & Transit Altitude
Puppis is centered near Right Ascension 07h 15m 36s, Declination −31° 10′ 48″ (The Poop Deck (Stern of Argo Navis)).
Practical Star-Hopping & Observing Tips
- Sweep 12° east-northeast of Sirius (Alpha Canis Majoris) with binoculars to capture the side-by-side contrast of open clusters Messier 47 and Messier 46.
- Increase magnification to 100×+ on Messier 46 (with a UHC or O III filter if available) to spot the 65-arcsecond smoke ring of planetary nebula NGC 2438 floating among the cluster stars.
- Scan around orange supergiant Pi Puppis (+2.71) and blue-white pair k¹/k² Puppis (magnitudes +4.5 and +4.6 separated by 9.9 arcseconds) in southern Puppis.
Notable Celestial Objects in & Near Puppis
| Object | Family | Classification | RA (J2000) | Dec (J2000) | Min. Instrument |
|---|---|---|---|---|---|
| Sirius (Alpha Canis Majoris Binary) | stars | Spectroscopic & visual binary (A-type main-sequence + DA2 white dwarf) | 06h 45m 08.92s | -16° 42′ 58.0″ | Naked eye (100–150 mm telescope under steady seeing to split Sirius B) |
| Carina Nebula (NGC 3372 Star-Forming Cloud) | nebulae | Giant H II region and massive OB star-forming complex | 10h 45m 07.00s | -59° 52′ 00.0″ | Naked eye and binoculars (south of 30°N) |
| Messier 46 (NGC 2437 & NGC 2438 Planetary Pair) | open-clusters | Rich open star cluster | 07h 41m 48.00s | -14° 48′ 36.0″ | 7×50 binoculars (150 mm+ telescope for NGC 2438) |
| Messier 47 (NGC 2422 Puppis Open Cluster) | open-clusters | Young open star cluster | 07h 36m 35.00s | -14° 29′ 00.0″ | Naked eye / 7×50 binoculars |
| Puppis A (Cosmic Cannonball Supernova Remnant) | supernova-remnants | Oxygen-rich core-collapse supernova remnant with central compact object | 08h 23m 00.00s | -42° 59′ 00.0″ | 250–350 mm+ telescope + O-III filter (or narrowband CCD/CMOS camera) |
Scientific Sources Cited
- IAU Official Constellation Boundaries & Designations (IAU 88 Recognized Constellations): Delporte, E. 1930, Délimitation scientifique des constellations (IAU / Cambridge University Press) — International Astronomical Union (IAU)
- SIMBAD Astronomical Database (CDS) (2026-10 release): Wenger, M., et al. 2000, A&AS, 143, 9 (The SIMBAD astronomical database) — Centre de Données astronomiques de Strasbourg