…continuedNebulae of the Deep South
Glories of Carina
The heart of the southern Milky Way is the magnificent Eta Carinae Nebula (NGC 3372), which North American pilgrims enthusiastically observe every February from Florida's Winter Star Party. This showpiece is framed by three naked-eye open star clusters: NGC 3114, the large and very bright IC 2602 (also known as the Southern Pleiades), and the football-shaped swarm of what is arguably the sky's finest cluster, NGC 3532. I zoomed in over the huge emission nebula's outer filaments, over its many silhouetted dust clouds, over the large scattered cluster Collinder 228 in its southern section, over its brilliant central masses bifurcated by a chevron-shaped dark lane, over the star sprays of the embedded clusters Trumpler 14 and 15, and then concentrated on the young stars of arrowhead-shaped Trumpler 16, a rich open cluster at the southern end of the dark Keyhole Nebula.
Trumpler 16 holds the very bright, very tiny (15") Homunculus Nebula, a bipolar shell of dust and gas that surrounds the supergiant star Eta Carinae (R.A. 10h 45m 03.6s, Dec. -59° 41" 04', equinox 2000.0). The intensely colored Homunculus Nebula is as orange as Antares. I studied it with ASNSW member Andrew Murrell's 20-inch f/5 Dobsonian at 363x on a very steady night at the site where the South Pacific Star Party was later held. Amazingly, I was able to see the major features that are visible on the Hubble Space Telescope image. The western lobe was narrower and had a tiny dusky inclusion; the eastern lobe was wider and had two tiny dark inclusions arranged along the Homunculus's major axis. Tiny spikes extended both northwest and southeast of the obscured star, with the northwestern spike being the sharper of the two. This detailed view of matter thrown off by the unstable star during its famous 19th-century outburst was perhaps the most exciting part of my trip.
The emission nebula NGC 3324 would be more famous were it not overshadowed by the nearby Eta Carinae Nebula. Seen through ASNSW member and South Pacific Star Party cofounder Tony Buckley's 14½-inch f/7 Dobsonian at 81x, NGC 3324 was a nebulous two-lobed patch. A bright yellow star adorns the southern lobe; the northern lobe of nebulosity is crescent-shaped. The view improved noticeably when a Lumicon ultra-high-contrast (UHC) filter was threaded onto the eyepiece. Intriguingly, the Millennium Star Atlas and NGC 2000.0 both suggest that a cluster is involved with this nebula, but none was apparent at the eyepiece.
The faint emission and reflection nebula NGC 3293 surrounds a splendid open cluster sharing the same NGC number. That cluster was an incredibly tight ball of stars in the 14½-inch at 81x. A line of three bright stars, one orange, highlights the center. A long, dark nebula coursed to the west of the open cluster, and a tiny one lay immediately to the east. Without a filter there was only a hint of the diffuse emission nebulosity seen in photographs. But with a UHC filter and a magnification of 136x the cluster was enmeshed in nebulosity, and the long dark lane became more obvious.