The Veil Nebula is the spectacular result of
a supernova explosion that occurred about 30,000 years ago
towards the centre of the two main arcs. This image shows the
western arc, designated NGC 6960. The bright magnitude 4 star in
the centre is 52 Cygni. The Veil Nebula takes its name from the
delicate filamentary structure of the expanding gas shells which
appear in different colors owing to temperature variations in
the gaseous elements that comprise the shell structure. This
shock front is effectively sweeping the interstellar gas and
dust as it expands, leaving the trailing region clearer with
many more stars visible. This can be seen clearly in the above
image by comparing the upper 'unswept' half of the image with
the lower 'swept' half.
