NGC 6559

Combination of 10, 3 minute images using red, green and blue filters.
SBIG ST-9XE CCD. 5" f/5 refractor at prime focus.

NGC 6559 is a small and rather faint emission nebula in Sagittarius, about 2 degrees east of M8. Some thin cirrus clouds drifted past while I was taking the red images, reflecting the city lights, which resulted in the red background being brighter.

Combination of 40, 1-minute images each with an H-alpha filter, an SII filter, and an OIII filter.
SBIG STL-1001E CCD. 5" f/5 refractor at prime focus.

The above image was processed using the H-alpha images as the red channel. This is the preferred palette of the European Southern Observatory. The HST observers prefer to use the SII images as the red channel since the SII line is at a slightly longer wavelength than the H-alpha line. This results in a more green-dominated image as shown below.

The above image processed using the Hubble Space Telescope palette.