The nebulosity surrounding Sadr.

This is a bicolor narrow band image produced according to Steve Cannistra's formula. The data is collected in Ha and OIII bands (in this case, 130 minutes of each). The RGB image is produced with Ha for red, OIII for blue, and (Ha)x(OIII) for green. The resulting image is balanced, smoothed, and so on, to produce this result.