Scutum (The Shield) & Wild Duck Cluster
Scutum IAU constellation (109 sq deg, rank 84): August Scutum Star Cloud gem between Aquila and Sagittarius, hosting the Wild Duck Cluster (M11) and M26.
Sky Navigation & Astrophysical Context
At just 109 square degrees, Scutum is the fifth-smallest of the 88 IAU constellations, yet it occupies one of the brightest and densest naked-eye regions of the entire Milky Way between the tail of Aquila and the star clouds of Sagittarius. Johannes Hevelius created the constellation in 1684 as 'Scutum Sobiescianum' (the Shield of Sobieski) to honor his patron King Jan III Sobieski of Poland following the 1683 relief of the Siege of Vienna; alongside Coma Berenices, it is one of only two constellations named after historical figures.
Our line of sight through Scutum looks through a dust-free window straight along the tangent of the inner Scutum-Centaurus Spiral Arm, producing the oval-shaped Scutum Star Cloud (4.5° across) that shines like an detached island of light on dark August evenings, flanked by the K3 III orange giant Alpha Scuti (+3.85) and the G4 Ib binary Beta Scuti (+4.22).
Hooked onto the northern edge of the Scutum Star Cloud just 1.8° southeast of Beta Scuti shines Messier 11 (NGC 6705, 'The Wild Duck Cluster,' V = +5.8)—arguably the richest and most globular-like open cluster in the northern and equatorial sky, packing nearly 3,000 stars (~250 million years old at 1.9 kiloparsecs) into a V-shaped flying-flock wedge around a +8.0-magnitude apex star. Scutum also contains open cluster Messier 26, the prototype high-amplitude pulsating star Delta Scuti, the RV Tauri prototype R Scuti (1° northwest of M11), and the extreme red hypergiant UY Scuti.
Equatorial Center Position & Transit Altitude
Scutum is centered near Right Ascension 18h 40m 12s, Declination −09° 53′ 24″ (The Shield (Sobieski's Shield)).
Practical Star-Hopping & Observing Tips
- Drop 3° southwest from Lambda Aquilae (at the southern tip of Aquila's tail) to see the glowing Scutum Star Cloud and aim at its northeastern corner for the Wild Duck Cluster (Messier 11).
- At 100×–180× in a 100 mm+ telescope, resolve M11 into a shimmering powder of hundreds of 11th- to 14th-magnitude stars arranged in a V around its bright central star.
- Check the bright RV Tauri supergiant variable R Scuti just 1° northwest of M11 in binoculars as it fluctuates between magnitudes +4.2 and +8.6, and hop 1° east of Delta Scuti for open cluster M26.
Notable Celestial Objects in & Near Scutum
| Object | Family | Classification | RA (J2000) | Dec (J2000) | Min. Instrument |
|---|---|---|---|---|---|
| Lagoon Nebula (Messier 8 / NGC 6523) | nebulae | Giant H II emission nebula with embedded open cluster NGC 6530 | 18h 03m 47.00s | -24° 23′ 12.0″ | Naked eye / 7×50 binoculars |
| Altair (Alpha Aquilae Rapid Rotator) | stars | Rapidly rotating A-type main-sequence star (Delta Scuti variable) | 19h 50m 47.00s | +08° 52′ 06.0″ | Naked eye |
| Wild Duck Cluster (Messier 11 / NGC 6705) | open-clusters | Rich compact open star cluster | 18h 51m 05.00s | -06° 16′ 12.0″ | 7×50 binoculars (spectacular in 100 mm+ telescopes) |
| UY Scuti (Pulsating Red Supergiant in Scutum) | variable-stars | Dust-enshrouded pulsating red supergiant variable star | 18h 27m 36.58s | -12° 27′ 58.9″ | 70–100 mm telescope |
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