Hubble's variable nebula is believed to be variable because the light
from an obscured pre-main sequence star is hidden by patchy clouds of
dust in orbit around it. Occasionally thinner regions allow some light
to escape to illuminate the outer nebula, which is seen to vary
erratically. These variations are seen in our colour picture. as coloured rims on
the peripherary of the nebula.
In 1985, Malin and Walsh found faint Herbig-Haro objects associated with the nebula and this photographically amplified image shows the faint extensions.