Sh2-157
is a large and faint nebula only 1° South-West of the Bubble Nebula
(NGC 7635). This image frames both objects, with the Bubble Nebula on
the lower-left corner. The main nebula resembles me a "Current Clamp",
but it is universally nicknamed "The Claw". More objects are framed: the
nebula encircling the bubble is
Sh2-162, while the yellow small globular nebula is GN 23.15.3. The small
isolated red nebula in the middle-left is Sh2-159. The open cluster on
the top border is NGC 7510. The bright and small red nebula near the
middle of Sh2-157 is LBN 537.
This image is an 8 h Ha-RGB
composition, with most of the exposure focused on H-alpha emission
(5.5 h) and only a few RGB (2.5 h). Unfortunately only a single night of
the new Moon weekend was clear; I would like to have collected at least
the double of the exposure for a best rendition. Be sure to look not
only to the
color version but also to the black and white Ha only version.
