With a few rare exceptions, when you look up at a clear night sky, everything you see lies within our personal galaxy of 100-400 billion stars, called The Milky Way. Galaxies come in many shapes and sizes. Ours is classed as a barred spiral, and resembles a four-armed child’s pinwheel (only a hundred light years bigger).
Our Sun and its planets orbit the centre of the pinwheel about two thirds of the way out from the centre along one of the pinwheel arms. Imagine the pinwheel is made of stars and picture yourself on a planet two thirds out from the middle. If you look toward an edge, you will see a scattering of stars, but if you look toward the centre, there will be many more stars in your field of view.
When you’re talking billions, they tend to blend together. That edge-on blended view is what forms that ‘milky’ band in the sky, giving our galaxy its name. Anyway, that’s a long-winded introduction to the fact that this is a great time of the year to view the Milky Way from any relatively darkish urban area once sunset’s glow has faded out (country folk have no problem – the Milky Way is too prominent to be missed). In late September and early October, the brightest part of the Milky Way stretches from the south – south west horizon, up the southern sky, to overhead. If you look south at about 8pm, Mars is the brightest object in the area. It lies in the constellation Sagittarius. To the west, you’ll find Saturn in Scorpius.
The actual centre of the galaxy lies between, and slightly below, a line between Mars and Saturn. Although it’s the brightest part of the Milky Way, the centre itself cannot be seen because it’s obscured by dust. If you shift your gaze overhead, you should be able to spot a prominent cross shape known as the Northern Cross (officially Cygnus the Swan), and to it’s west, bright Vega in the constellation Lyra. Sagittarius, Scorpius, Cygnus and Lyra, and the eight or so constellations in between, hold some of the northern hemisphere’s best astronomical objects. Scanning the area with binoculars from a dark sky will provide many interesting sights; through a telescope, there’s a lifetime of fascinating objects to study. While it’s possible, from a dark corner of your back yard, look beyond the nearby stars and glimpse the edge of our galaxy itself, the Milky Way can only be fully appreciated from a dark rural sky. Seeing the enormity of our home galaxy stretched out before us tends to put our place in the universe into perspective.
A dark sky view of our Milky Way should be on everyone’s bucket list. There are few sights more humbling.
