Bubble Nebula NGC7635
Bubble Nebula
Emission Nebula in Cassiopeia



M82: The Bubble Nebula is formed around a massive bright blue star, which is emitting a fast stellar wind of ionized gas. As fast moving gas expands off the central star, it pushes surrounding sparse gas into a shell. The energetic starlight then ionizes the shell, causing it to glow. The nebula, also known as NGC 7635, is visually located on the edge of the constellation Cassiopeia. The Bubble Nebula is thought to be a rare example of a very massive star, with an extremely strong stellar wind, located within a gas cloud. It can be seen that this outward wind results in an expanding shock-wave which forms this "bubble" in space. The "bubble" itself is estimated to be about 10 light years across, more than twice the distance from the Sun to the nearest star; estimates vary regarding its distance from earth, with 7100 light years being the most common figure given.


Technical Information:

RRGB: RRGB image (220:75:75:120) (LR, R and G were integrations of five minute images, all umbinned; B was an integration of eight minute images, all unbinned).

Equipment: 10" LX200 at f/4.6, and an SBIG ST-7E camera/CFW-8 color filter wheel

Image Acquisition/Camera Control: CCDSoft V5.

Processing: All images calibrated (darks and dawn (fog) flats) and registered in AIP4WIN. Luminance images add combined in CCDSoft; RGB median combined in CCDSoft. Luminance layer had DDP and Richardson-Lucy applied in AIP4WIN, and maximum noise reduction applied in PhotoShop. Color combine, and adjustment of curves, performed in Photoshop 5.5.

Location: My back yard in Bellevue, Washington, elevation 600'.

Date: All images taken during the nights of 8/24/01 and 8/25/01.

CCD Temperature: -18C

Copyright Mark de Regt, 2001