|This week, observers in the Southern Hemisphere looking west just after sunset will have a fine view of the planet Mercury. This will be the view from Melbourne half an hour after sunset. |
Starry Night Software
Even though Mercury is one of the brightest objects in the sky, very few observers have ever seen the planet in the night sky. That's because it never strays very far from the sun, and is usually lost in its glare.
Earlier that day, Mercury also passed about half a degree south of the bright star Spica in the constellation Virgo. (Your closed fist held out at arm's length covers 10 degrees of the night sky).
Mercury is slightly brighter than Spica. Further up in the sky, the planet Saturn is intermediate in brightness between the two.
I find the best time to spot Mercury is about half an hour after local sunset. Even then, binoculars are helpful to spot Mercury. Once spotted in binoculars, it’s usually easy to see with the naked eye.
Northern observers will have to wait until early November to catch a view of Mercury in the dawn sky.
Also this coming week, on Tuesday, Sept. 23, the sun will reach its equinox, crossing the celestial equator moving southward. This marks the first day of autumn in the Northern Hemisphere, and the first day of spring in the south.