Bubble Nebula in Cassiopeia

This is a vast sphere of tenuous gas that is sometimes classified as a planetary nebula.

Images taken with TEC-140 Telescope mounted on Losmandy G11 mount. Camera used was a Canon EOS20D used at prime focus.

Fifteen 3 minutes exposures dark compensated, aligned and stacked, background removed and Digitaly Developed in ImagesPlus 2.01