The Eastern Veil nebula (also known as Caldwell 33) is a cloud of heated and ionized gas and dust in the constellation of Cygnus and is located at around 1470 light-years from Earth. It is part of the Cygnus Loop which is a faint supernova remnant that exploded approximately 7000 years ago. From the moment the source star exploded and until now, the Cygnus Loop supernova remnant expanded to a diameter of roughly 3° on the sky (that almost 6 full moons). The red hues in this image are from ionized hydrogen content of gas clouds that emit light in the H-alpha wavelength, while the cyan hues are from oxygen ions.