Sometimes stars that would be recognizable in summer can be puzzling these evenings, rotated halfway to the left as they are just starting to emerge over the Rockies. What, for example, are those stars below Ursa Major? Recall last column, we followed the Big Dipper’s handle in an arc down to Arcturus — bright star in Boötes — and noticed it, with two other stars in Boötes and Corona Borealis, forming an equilateral triangle. Next, note low over the Rockies to the northeast the glowing band of the Milky Way starting to rise. In it, tilted on its side, is t-shaped Cygnus. Between Cygnus the Swan and coronet-shaped Corona Borealis, find a rectangle wider along one end — the constellation Hercules — tilted left from its more common summer view. Closer to Ursa Minor winds Draco. Below and left of Hercules is bright star Vega.
There is a special reason to note Hercules. Very close by is the direction our solar system is moving around the galaxy! Isn’t Hercules above the plane of the galaxy? Yes, and like many stars, as everything rotates around the Milky Way, our Sun’s path wanders up and down a slight amount over and over. We are also currently getting slightly closer to the centre of our galaxy. And where is that galactic centre? From this far north of the equator, it is just below our southern horizon in summer. [On the chart, note the direction of Polaris, indicating Earth itself is angled. And since our solar system is also tilted, over sixty degrees to the galactic plane, no wonder we see the Milky Way at various odd angles throughout the year!]
Looking to the west for a few evenings now, if you can find a view where the sun has just set and the mountains are low, you might spot with binoculars bright Venus, the much more remote Jupiter and maybe even the closer-to-us but tiny, elusive Mercury, all dancing visually next to each other. Delightfully poetic… and no tilting needed.
Brian Fenerty is a semi-retired valley resident and an esteemed member of the Royal Astronomical Society of Canada. Contact him at firstname.lastname@example.org.