South America in 2019 will have more than just a Total Solar Eclipse to dazzle eclipse-chasers
Visitors to Chile, northwest Argentina or the South Pacific, know that you will be greeted by a whole new set of Southern Hemisphere constellations, bright stars and stunning objects only viewable from these latitudes; there’s a reason why astronomers have chosen Chile to build the very biggest and best ground-based telescopes.
Judged purely on targets, the Southern Hemisphere the best place to be for stargazers. While the north pole faces outwards to the Universe beyond, the south pole points to the galactic center of the Milky Way. That has obvious consequences for stargazing; there are billions of stars, and more bright stars, more constellations containing more objects in the southern skies. For stargazers, it’s hard to resist. Here’s a hit list of the top sights in the Southern Hemisphere to search for in June and July, adapted from my book A Stargazing Program For Beginners: A Pocket Field Guide published by Springer.
You get your own view of what the world’s biggest telescopes in Chile are looking at every night by aiming your binoculars or a telescope at these sights:
6 – Omega Centauri (NGC 5139)
A globular cluster with the naked eye? This 13 billion year old, one million star-strong globular will appear under dark skies as a fuzzy blob to the naked eye, a bright bulge in binoculars, and plain stunning in any size of telescope.
Go back to the Southern Pointers, and locate Beta Centauri, the star nearest to the Southern Cross. Above Beta Centauri is Epsilon Centauri, or Birdun. Check you’ve gone the right way by making an equilateral triangle with Beta Centauri, Epsilon Centauri and Becrux on the left-hand side of the Southern Cross. We’re now deep into the constellation of Centaurus. Visualize a line between Beta Centauri and Epsilon Centauri, and go the same distance again, and you have found Omega Centauri. It’s thought to be the nucleus of a dwarf galaxy that collided with our own.
7 – Centaurus A galaxy (NGC 5128)
Range your binoculars up from Omega Centauri and you’ll come to Centaurus A, or NGC 5128, the fifth brightest galaxy in the sky. Part of the Virgo Supercluster, Centaurus A is 11 million light years away and is actually two galaxies crashing into each other, though you’ll need a small telescope to discern the vast dust lane across the middle. In a very dark sky, you may be able to glimpse this unusual galaxy with the naked eye.
8 – Saturn
Think this is a global sight? Since it traverses the same ecliptic as the Sun and the rest of the planets, technically the Ringed Planet can be seen from anywhere on Earth. However, it’s currently moving through the zodiacal constellations that are low on the southern horizon for us in the northern hemisphere. Consequently, Saturn is often lost in the haze and can be impossible for backyard stargazers to glimpse for months on end. That’s not going to get any better anytime soon, as Saturn – on its 29 year orbit around the Sun – will move through the constellations of Scorpius, Ophiuchus, Sagittarius and Capricorn until the mid 2020s. All of those constellations are easiest to see, and high in the sky, from April to August in the southern hemisphere.
9 – An upside-down Moon
What phase is the Moon in? From the southern hemisphere, it can be difficult for northerners to tell when they first arrive. Everything northerners see in the southern part of the celestial sphere – including along the the ecliptic – will appear upside-down when we cross into the southern hemisphere. That includes the Sun and Moon. Here’s the proof that we don’t live on a flat planet. Since it orbits near the equator, the Moon is therefore not only in the northern sky, but it’s upside-down, so its phases appear to be backwards. As viewed from the southern hemisphere, the Moon is slowly lit from right to left as the New Moon waxes towards Full.
It all makes perfect sense, but take a closer look at the Moon through binoculars and the sight of the Sea of Tranquility, Sea of Serenity and Sea of Fertility all orientated the ‘wrong’ way is strange indeed.
10 – Sagittarius Arm of the Milky Way
Though it’s impossible for us to get a bird’s eye view of the galaxy we live in, but we can get our very best views of it only from the southern hemisphere. Down here we can see the Milky Way’s innermost, brightest Sagittarius Arm – it glows because it covers the galaxy’s bright core – and we can see the Great Rift, a spectacular dark nebula of dust clouds. These clouds, which look like dark areas between the rich star-fields of the Milky Way, are only about 300 light years away (the center of the Milky Way is 25,000 light-years distant), and they block our view of the stars behind.
It’s very easy to find. We’ve already looked at the Milky Way descending through the Summer Triangle from Deneb through Altair. It’s here that the Great Rift begins. Find Deneb or Altair (which will be highest in the sky) and trace the Milky Way across the zenith and down to Alpha Centauri and the Southern Cross above the southern horizon. It’s a demonstration of just what we miss out on in the northern hemisphere.
The best time to see the Great Rift is between July and September, when the Milky Way stretches overhead in the southern hemisphere.