NGC 7635 - The Bubble Nebula in Cassiopeia
Copyright 2002 John Hodge
The almost round 'bubble" in this photo is caused by fast stellar "wind" from a central star, known as BD+602522, impacting sparser areas of hydrogen gas and pushing them into a spherical shell. The star's radiation then causes the shell to glow. The bubble itself is about 10 light years in diameter and lies at a distance of 11,000 light years.
August 2002 Iwancio-Hodge Observatory
Instrument: SBIG ST-7 through 12" LX-200
Focal Ratio: f 10
Guiding: Auto via ST-7
Conditions: Visually clear, but with moderate high level water vapor