A unique celestial object, a soap bubble-shaped nebula called ngc7635, discovered in 1787 by William Herschel, an English astronomer. The nebula is located in the constellation of Cassiopeia (between Cassiopeia and Cepheus in fact) and its diameter is about 10 light years. This bubble shape is designed thanks to the stellar wind created by the star SAO 20575, just next to it, a little off-centered, very dense and warm. This star is expected to explode as a supernovae in a few tens of millions of years.

This image results from the composition of photos taken with different color filters and in H-Alpha for fine details.