About half an hour after sunset tonight (Nov. 28), Mercury will shine close to Saturn in the early-evening sky for the first of three close approaches between the two planets.
Mercury and Saturn will shine about 3 degrees apart from each other low in the southeast; 3 degrees is about the width of your thumb held up toward the sky, according to an article on EarthSky.org. Mercury is about twice as bright as Saturn, and both planets should be visible through binoculars in the same field of view. So try that method if you can't discern both by eye. [The Brightest Planets in November's Sky]
The planets' approach marks the first of three conjunctions, or close approaches, of the two, which will get closer each time. On Dec. 6, Mercury will be less than 1.5 degrees away from Saturn, or about half the distance of this month's conjunction. Then, on Jan. 13, Mercury will be just 0.7 degrees from Saturn — about the width of a pinky finger held to the sky, according to EarthSky.org. While the Dec. 6 conjunction will be obscured by the glow of sunset, the Jan. 13 one will be visible in the morning sky below a waning crescent moon.
Mercury and Saturn may look close during this triple conjunction, but (of course) this is an illusion — the two planets will be separated by about 10 times the distance between Earth and the sun during all three of their close approaches, according to calculations by Wolfram Alpha.