As day ebbs into night, will you spot the young lunar crescent and the star Regulus as they make their fleeting appearance over the western horizon at dusk? From mid-northern North American latitudes, you might catch the elusive couple about 45 to 60 minutes after sunset – if you’re blessed with an unobstructed western horizon and crystal-clear skies. Binoculars may be helpful.
It’ll even be even harder to catch the thin waxing crescent moon at mid-northern latitudes in Europe and Asia, because the moon sets earlier there than it does in North America. The Southern Hemisphere is really the right place to be for seeing this evening’s young moon and Regulus, as they’ll stay out till after dark in that part of the world.
There’s a good reason why the young moon and Regulus are so much easier to spot at southerly latitudes. It’s because the ecliptic – the pathway of the sun, moon and planets – hits the horizon at a much steeper angle as darkness falls at this time of year in the Southern Hemisphere. At southerly latitudes, the young moon and Regulus are higher in the sky at sunset, and therefore stay out longer after sundown.
Regulus wins acclaim for being the only first-magnitude star to reside almost squarely on the ecliptic. In about a month from now – on August 22 – the sun will have its annual conjunction with Regulus. At that time, Regulus will be invisible from everywhere worldwide, as this star will rise and set with the sun on this date.
Bottom line: See if you can catch the young moon and Regulus after sunset on July 29, 2014! Look as soon as the sky begins to darken – in the sunset direction. They’ll be low in the sky. Use binoculars if you need them.