The Pacman Nebula,NGC 281

Firstly, I captured many images of this subject, with a monochrome astronomy camera. To create a color image, I use many different filters and then map the images through each filter to red, green, and blue. For this image, I captured broadband 60-second exposures of red (20), green(20), and blue(20), and narrowband 300-second exposures of Hydrogen-alpha(17), Sulfur-II(23), and Oxygen-III(15). This gives a total of 5 hours, 35 minutes for all filters.

I processed this image in the program PixInsight. I extracted sky backgrounds for every image. Then, I combined each filter's data to create a color image. Afterwards, I did several adjustments including a "histogram stretch" to massively brighten the nebula. Other adjustments include contrast, saturation, and adjusting various blending of the images. This image is a blend of narrowband data to extract the nebula and broadband data to capture the vibrant star colors of the dense starfield throughout the region.

This image was taken over one night. By far the biggest challenge was the moon. Moonlight does not affect Hydrogen-alpha and Sulfur-II data, however Oxygen-III data is a different story. Oxygen-III's emission wavelength is right where the moon glows brightest, so extracting the blue oxygen components you see in my image was a challenge in terms of noise reduction and background gradient removal. Additionally, I only had one clear night to do this, so filter time management was critical.