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This is a partially-zoomed-in view of The Heart Nebula in Cassiopeia. This nebula (more formally known as Sharpless 190) is often called IC 1805, but strictly speaking that designation applies just to the star cluster to the right of center; this cluster is also known as Melotte 15.
This patch of sky is rich in all three narrowband components (H-alpha, O-III, and S-II) and full of interesting color and detail. Note again (as we did with the previous image, Sharpless 171) how most of the structures point towards the star cluster. This is because all the red/orange gas is being pushed away from the center of the picture.
This tricolor narrowband image is the result of Ha:OIII:SII = 4:4:3 hours of exposure (11 hours total).