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Log, Apr 4, 2008

No people. We've been having a series of rainouts while I've been away leaving Francine to wonder if somehow I managed to drag the good weather into the southern hemisphere. Well if I did, I haven't the foggiest (or rainiest or whatever-iest) idea how I did it. I actually had some excellent viewing weather along with some really amazingly bad weather which I prudently avoided by pulling the covers up over my head and sleeping through it.

The weather around Cape Horn is famously bad. Storms at sea are measured in the Beaufort Scale (1-12) where 1 is dead calm and 12 have 30+ foot waves breaking over the top decks of ships like oil tankers. Our cruise ship has 14 complete decks plus 3 partial decks above that but the night that our ship encountered Beaufort 10/11 conditions, our balcony on the 9th deck (almost 80 feet from the water) was drenched with mist from the tops of waves that turned into foam as the ship hit them. It took Ferdinand Magellan 38 days to travel through the Straits which bear his name. Of course he was tacking a sailing vessel in a fairly narrow channel AGAINST the winds. We were going with the winds and had the engines of a huge cruise ship and it took us only a day and a half of sailing.

The sky above the ship was breathtakingly dark. The ship was brightly lit but I found an completely shielded area at the bow which was pitch black leaving me with excellent views of the parts of the sky which I had never seen before. When we turned east, my own balcony was ideal for viewing. I simply turned off the cabin lights. Since deck 9 actually sticks out from the rest of the ship, lights behind me were not visible.

My principle targets were the Large [LMC] and Small [SMC] Magellanic Clouds. I saw them easily both by eye and even more spectacularly through my large astronomical binoculars. I debated with myself for a month before leaving whether I would take my binoculars or my 3.5 inch Questar. Since my platform was a rolling ship, I opted for the binoculars and I am glad I took them.] They were the last two objects left on my life list of over a thousand objects I wanted to see some time in my viewing career.

Although they were not on my list, Eta Carina and Omega Centauri were also first time views for me. Eta Carina is a huge unstable star which seems just on the point of being ready to supernova. If so, it will give us the first close up of the death of a star since the invention of the telescope. Omega Centauri is the nearest globular cluster to the solar system. It was easy to see with the naked eye.

I have to say that Omega Centauri is so much bigger and easily seen than its runner up [M13 - the Great Hercules Cluster] that it is like comparing a giant to a child.

I had seen the Southern Cross [Crux] and the lower parts of Centaurus before [the upper parts being visible from as far north as New England] when I traveled to the Caribbean, but they were on the horizon and not very spectacular. From more than 45 degrees south latitude they were stunning. Several people on the cruise ship were trying to find the Southern Cross unsuccessfully. They were looking for the wrong shape. The "cross" is really much better described as the "kite". This is especially true if you create an "asterism" from the kite [Crux itself] and add a kite string from the bright stars of Centaurus and Triangulum Australe.

In the famous Sherlock Holmes mystery - Silver Blaze, the significant clue is "the dog which didn't bark." The southern sky has its equivalent - "the pole which doesn't shine". The north celestial pole is almost perfectly aligned with a fairly bright second magnitude star Polaris [a.k.a the Pole Star or Alpha Ursa Minor]. You simply use the pointer star of the Big Dipper to find a reasonably bright star all by itself and you are within a fraction of a degree of true north. Not so, in the southern hemisphere. The main axis of Crux points at the south celestial pole but when you get there, there is nothing eye popping to use as a clue. The southern pole is in a stunningly uninteresting constellation called Octans whose claim to fame is nil. If you follow the main axis of Crux until you finally hit the SMC, you've gone too far. Back up about a quarter of the way and you'll be close to the south celestial pole.

One thing which is confusing at first is that the familiar constellations of the equatorial and northern skies are upside down. Orion stands on his head as if he was in the process of turning a cartwheel. Going down from Rigel across the belt to find Betelgeuse just ain't normal. The Moon's marking are upside down. At least this is ok because with various eyepieces and right angle mirrors I have seen the Moon in every rotation and reversal before. The Sun, the Moon and the planets are all in the north [I saw Jupiter, Mars, Venus and Mercury].

One object eluded me, but I was smart enough never to put it on my "life list". The southern sky hosts "Proxima Centauri" - the nearest star outside the Solar System. It is part of a trio of stars that are gravitationally bound - Alpha-1, Alpha-2 and Proxima. Alpha-1 and Alpha-2 are quite similar in absolute magnitude to the Sun and close enough that combined they are the 4th brightest star in the sky. They go around each other in about 80 years. Currently they are about 8 arc seconds apart - wide enough to be almost split able in my binoculars. Sometime around 2060, they will be 22 arc seconds apart, easily split in large binoculars. Proxima is more 2 degrees (7200 arc seconds) away from its two larger siblings. [At an angular distance greater than 4 Moon diameters - this makes quite a split!]

Little Proxima is so dim that even though it is the closest extra solar star that it is only the 11th magnitude, over 10,000 times dimmer than Alpha-1. Even in my big binoculars, I couldn't see it. Yeah, I tried even though I knew it wouldn't happen.

Well, enough of "what I did on my southern vacation". It was the fulfillment of a boyhood dream to see all the stars of the heavens [or at least all the bright guys].

-Les Coleman

Leslie Coleman
Author:
Leslie Coleman
Entry Date:
Apr 4, 2008
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Leslie Coleman's Log
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