Lobster Nebula (NGC 6357)

NGC 6357
NGC 6357: Lobster Nebula with dark cloud B 258; Takahashi TOA 150/1100 APO refractor @ f/5.6 (TOA-645 Reducer); SBIG STL-11000M; Astro-Physics 1200GTO; 27x5 min -25 °C; Namibia, Tivoli Southern Sky Guest Farm, 1360 m ASL; © 2. 9. 2016 Manuel Jung [45]
NGC 6334 + NGC 6357
NGC 6334 + NGC 6357: Cat's Paw Nebula and Lobster (or War & Peace) Nebula; Takahashi FSQ 106/530mm; SBIG STL11000M/C2; R 9x10 min; G 8x10 min; B 9x10 min; -25 °C; Astrofarm Tivoli, Namibia; © 2012 Hansjörg Wälchli [46]


The nebula was discovered by John Herschel on 8 June 1837, when he was in South Africa exploring the southern sky with his homemade 18¼ inch reflecting telescope. He catalogued the nebula as h 3682 and noted: «Faint, large, extended, very gradually little brighter in the middle, milky nebulosity, 2' long, 1 1/2' broad, close to and almost involves a double star.» [467] Dreyer then adopted the nebula including the description in 1888 as NGC 6357 in his «New General Catalogue». [313]

The American astronomer Stewart Sharpless searched in the 1950-ies the photo plates of the «Palomar Observatory Sky Survey» made with the 48 inch Schmidt telescope. In 1953 he published the first release of his catalogue, where the nebula was listed as number 8 (Sh 1-8). In 1959 he published the final release, where the nebula got the designation Sh 2-11. He described it as a bright, irregular nebula with filaments and of 90 arcminutes in size. [309, 310]

Physical Properties

NGC 6357 is a galactic star-forming complex at a distance of approximately 1.7 kpc. It consists of several HII regions, which is glowing hydrogen gas ionized by the intense ultraviolet radiation from massive young stars. The nebula also contains a few young stellar clusters, and giant molecular clouds. The HII regions G353.2+0.9, G353.1+0.6, and G353.2+0.7 are associated with three young clusters, among these the post prominent one is Pismis 24 (Pi 24), which contains some of the most massive stars known. [49] Star Pismis 24-1 was once thought to have an incredibly large mass of 200 to 300 solar masses. Hubble Space Telescope measurements of the star, however, resolved this into two separate stars, and therefore halved its mass to around 100-150 solar masses. [297]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Designation NGC 6357
Right Ascension (J2000.0) 17h 24m 43.5s
Declination (J2000.0) -34° 12' 05"
Diameter 25 × 25 arcmin
Metric Distance 1.800 kpc
Dreyer Description F, L, E, vglbM, D * inv
Identification, Remarks h 3682; GC 4297; ESO 392-SC10; CED 142; Sh2-11

Finder Chart

The cluster NGC 6357 with nebula is in the constellation Scorpius. The best time to observe it is during the months of April to August, when this part of the constellation is highest above the southern horizon at night. An observation site with an unobstructed view to the south is required here, because the nebula has a declinination of -34°. Roughly 2° to the southwest lies the Cat's Paw Nebula (NGC 6334).

Finder Chart Lobster Nebula (NGC 6357)
Lobster Nebula (NGC 6357) in constellation Scorpius. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 15°