Antares and M4

The Antares/M4/Rho Oph region is probably my favorite in the entire night sky. Wider photos with longer exposure times show an incredible display of nebulae, both bright and dark. The globular clusters M4 and NGC 6144 make this small region of sky even more interesting. Unfortunately, when this photo was taken, the sky was too bright for long exposures and the nebulae didn't make much of an appearance.

Sizes available: 640x520 (97kB) | 1280x1038 (300kB)

The four brightest objects, clockwise from upper-left, are 22 Scorpii, σ Scorpii, the globular cluster M4, and Antares (α Scorpii). Just above and right of Antares is the smaller globular cluster NGC 6144. The faintly visible yellow reflection nebula surrounding Antares is designated IC 4605. The blue reflection nebula around 22 Scorpii is actually more of IC 4605. Similarly, the dark cloud in the upper-left is designated dark nebula B44, though it is technically part of the same cloud of dust as IC 4605. In this photo, there is what appears to be a faint blue reflection nebula around σ Scorpii, but this is actually just the nearby bits of emission nebula Sh2-9.

The greenish object with the red halo, just left of M4, is some sort of camera artifact and is not a deep sky object. The vertical bar-like structure in the center of M4 (more readily apparent in the larger version) is actually there, however. It is a feature unique among the known globular clusters.

Exposure Data: