Tonight, a challenge … look for the young moon, the planet Saturn and the star Antares in the constellation Scorpius. Will you see them? On this night – October 25, 2014 – the trick will be to look as soon as possible after sunset, just as the sky is getting dark. At northerly latitudes, Saturn and Antares will soon disappear into the glare of evening twilight, if they haven’t done so already for your sky. The sky chart at the top of this post is for about one hour after sunset on October 25, 2014 at mid-northern latitudes in Northern America. Saturn and Antares will be similarly positioned, though the moon will be thinner in phase and lower in the sky, for Europe and Asia on this date.
For Southern Hemisphere observers: You’re in luck. It’ll be easier to see the moon, Saturn and Antares from the tropics and Southern Hemisphere. At southerly latitudes, all three lodge higher in the sky at sunset and stay out longer after sundown.
Anywhere at northerly latitudes, it will be quite a challenge to catch the young waxing crescent moon, Saturn and the star Antares close to the horizon as dusk ebbs toward darkness. You may need binoculars to see the threesome because all three follow the sun below the horizon before nightfall.
If you can’t see them tonight, don’t worry! The waxing crescent moon moves about 12o eastward of the sun daily. Your fist at an arm length approximates 10o. So watch the moon over the next few days, as it goes farther east of the sun and approaches the red planet Mars. This movement of the moon from night to night, by the way, is due to the moon’s actual motion in orbit around Earth.
Even on October 25 – and definitely for the next few evenings after that as the moon moves higher in the western twilight sky – it’s be easier to spot the red planet Mars than Saturn and Antares. At mid-northern latitudes, Mars is now setting about two hours after nightfall. That’ll be the case for the rest of this year.
Mars alternates good years and bad years in our sky; that is, in alternate years, it gets much brighter and is more prominent. 2014 was a good year, and Mars was brightest and easiest to spot around April. The planet is now in a long decline in our sky, hovering near the sunset glare. In fact, as viewed from above the solar system, Earth is racing far ahead of Mars. The planet is far across the solar system now nearly along our line of sight to the sun. But Mars own motion in orbit is keeping the planet from dropping into the sun’s glare just yet. Watch for a much-subdued Mars for the rest of this year.
What’s this? Yes, some awesome and prominent deep sky objects are now located near Mars along our line of sight. Before the moon gets too bright, try to spot the Lagoon Nebula (Messier 8) and Trifid Nebula (Messier 20) near Mars in binoculars or a low-powered telescope. In a few more days, moonlight will probably obscure the view.
Bottom line: The young waxing crescent moon, Saturn and the star Antares will be tough to spot on October 25, 2014 for N. Hemisphere observers as dusk ebbs toward darkness. Easier from the S. Hemisphere! By October 26 and 27, the moon will be moving upward in the west after sunset, and it’ll soon sweep near Mars.