The Bubble Nebula is a great imaging target, very difficult (IMHO) to get just just right. I’ve yet to do it. This is an incredible image from Hubble is a composite of separate exposures acquired by the WFC3/UVIS instrument.
For the 26th anniversary of Hubble’s launch on April 24, 1990, the telescope has photographed an enormous, balloon-like bubble being blown into space by a super-hot, massive star. Astronomers trained the iconic telescope on this colorful feature, called the Bubble Nebula, or NGC 7635. The bubble is 7 light-years across — about one-and-a-half times the distance from our sun to its nearest stellar neighbor, Alpha Centauri. The Bubble Nebula lies 7,100 light-years from Earth in the constellation Cassiopeia. – Hubblesite
Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)