CCD Sky Observatory

Images by Christopher Cappelli

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NGC 7635 - The Bubble Nebula

NGC 7635, also known as the Bubble Nebula, is approximately 11,000 light years from Earth in the constellation Cassiopeia.  It is believed that the "bubble" is caused by stellar winds originating from a young star at the center that influence the gas and dust of the nebula.

The data for this image was acquired on September 20th, 21st, 22nd, and 23rd, 2008 at the CCD Sky Observatory in Redlands, California, USA.  The final image seen here represents the combination of 16 hours of exposures (25 x 20-minute Ha (3nm) exposures and 25 x 20-minute OIII (3nm) exposures) taken with a Takahashi FSQ-106ED telescope and a QSI 532wsi camera cooled to -10° C.

The two sets of sub-exposures (Ha and OIII) were processed using CCDStack and Photoshop CS.  The images were calibrated, registered, normalized, STD sigma reject and combined in CCDStack.  The two resulting images (Ha and OIII) were  then brought into Photoshop for final processing.  Noel Carboni's Astronomy Tools for Photoshop were used for local contrast enhancement, and to synthesize a green channel from the red channel (Ha) and the blue channel (OIII).  Some additional processing was also done in Photoshop to balance the color and contrast of the image.