Thursday, February 23, 2012

1499n 2012/02/22–23

1499n 2012/02/22–23 21:30–23:25 Australian EDT Warrumbungle 8–9 ne 10x50b 36cmrl 76cmrl

For my second night in Warrumbungle, I used a 14-inch (356-mm) Newtonian with an f/4.5 mirror by Carl Zambuto, focal length 1600 mm. With Paracorr installed, the effective focal length is 1840 mm. I used 22 mm (84x) and 12 mm (153x) Naglers. It had Argo Navis and Servocat installed, but I decided to use its 8x50 straight-through finder and my Sky & Telescope Pocket Sky Atlas instead, because I wanted to find stuff myself. Nice hardware!

I used Alan Whitman's "Southern Hemisphere Splendours" list from the RASC Observer's Handbook as my working list. My first target was the very red star DY Crucis or Ruby Crucis, a tiny red speck located right next to brilliant Beta Crucis.

Centaurus was rising in the southeast so I caught three of its showpieces. First was Alpha Centauri, closest star to the Sun and a fine double, visible by its elongation at 84x. Next was Omega Centauri, the brightest globular cluster in the sky, or perhaps the stripped core of a dwarf galaxy. It filled the Nagler 22's 82 degree field with brilliant stars, resolved to the core. Nearby was one of my personal favourites, NGC 5128. This is a pair of galaxies in collision, the dust of one galaxy backlit by the light of the other. It is one of the brightest radio sources in the sky, Centaurus A. In the 14-inch it resembled its Australian popular name, the Hamburger Galaxy. John Bambury stopped by and remarked how the "lettuce" in the hamburger was visible.

The Small Magellanic Cloud was sinking in the southwest, so I checked out that area. Only in the southern hemisphere do you use naked eye galaxies to aid in star hopping. Just below the SMC is my very favourite southern object, 47 Tucanae, a globular cluster so brilliant and concentrated that it was mistaken for a star by early astronomers. It beats our more famous Omega Centauri for the title of "most beautiful globular cluster." Once again, the 14-inch resolved it to the core. The major difference between these two clusters is the degree of concentration of the core: 47 Tuc has a far more concentrated core, making it a mor brilliant sight.

The Small Magellanic Cloud, as one of the Milky Way's satellite galaxies, is chock full of deep sky objects. Along its eastern edge I observed two brilliant diffuse nebulae, NGC 460 and IC 1660, and a globular cluster NGC 419. Just to the west of these three is a beautiful little globular, NGC 362, a companion of the Milky Way rather than the SMC.

To finish up the night, I explored the incredibly rich area of the Milky Way in the constellation Carina. Just to the west of the Southern Cross, it includes two outstanding open clusters, the Football Cluster (NGC 3532) to the north and the Southern Pleiades (IC 2602) to the south. The Football has, as its name implies, an elliptical shape, and is considered by some the finest open cluster in the sky because of its large number of bright yellow stars, very unusual for an open cluster. The Southern Pleiades are fully worthy of their name.

Just west of these open clusters is the amazing Eta Carinae nebula. A wreath of brilliant nebulosity encloses an intensely dark nebula known as the Keyhole. Finally, right next to the bright star that gives this area its name, is the Homunculus. In Hubble images it looks like a tiny brain; in the 14-inch it is a remarkable brown colour. This is one of the few deep sky objects to show any colour. A rapidly evolving area, it actually looks different than it did the last time I saw it three years ago. This is the only time I have ever witnessed a change in a deep sky object in a lifetime of observing.

While exploring Carina, I was called over to take a look at the remarkable Spiral Planetary Nebula, NGC 5189 in Musca, which had been located in the 30-inch Obsession. This looked like a Hubble image: a swirl of overlapping arcs. Even in my "little" 14-inch, the multiple spirals were visible.

By this time the dew was becoming heavy, and I knew I had to get to dialysis first thing in the morning, so I called it a night. Very satisfying!

Temperature: 19C

No comments:

Post a Comment