m57

M57, a planetary nebula. Gonna have to get the big telescope out for this one. Gas emitted from a dead star at the end of its life, 2300 light years away the former red giant star left ionised gas as it contracted to a white dwarf.

Exercise in dither. No dark frames. Using the sinisterly named kappa sigma clipping algorithm.in DSS. No idea why it works but it does.

It's there in the centre somewhere