Sh2-157 + Massimo Di Fusco + L-UItimate

Sh2-157

Credit:  Massimo Di Fusco

Filters: Optolong L-UItimate

 

 

 

Sh2-157, also known as the Lobster Claw Nebula, is a faint but remarkably extensive emission nebula visible in the constellation Cassiopeia; it is located on the Perseus Arm and is directly connected to the large OB Cassiopeia OB2 association. The northern part of the cloud has a ring shape, caused by the action of the stellar wind from several giant stars, while the southern sector appears excited by the luminous radiation of stars of spectral class O.
Inside it is a cluster of very young stars, representing the latest generation of a star formation process that includes the Cas OB2 association itself and the nearby open cluster NGC 7510.
The nebula contains some very compact regions, the most conspicuous of which is Sh2-157A; this is a concentration clearly visible in the Hα band, in which the main source of gas ionisation appears to be an O8 or B0 class star. The cloud can be divided into two components: Component A, corresponding to the optically visible cloud, and Component B, which consists of the dark region detectable in photographs. The amount of ionised hydrogen present in Component A is significantly less than the mass of the central star, suggesting that there is also a certain amount of neutral hydrogen present. Component B, on the other hand, is composed of unilluminated dust. Its distance is comparable to that of the diffuse nebula behind it, of which it is part. A second, less bright agglomeration has been catalogued as Sh2-157B.

 

 

Konus 200/1000 @950mm, f/4.8
Player One Poseidon-C camera
Sky-Watcher Eq6r Pro Mount
Optolong L-Ultimate filter 244x300"
APP, PixInsight, PS
Ferrara (Italy)

Hope you like it.