Use the dazzling planets Jupiter and Venus to locate Mercury near the horizon
Make Mercury a priority in early March, for the first week of March will feature the Northern Hemisphere’s best opportunity to catch Mercury in the evening sky until June 2012. First thing, after sunset, look for the dazzling planets Venus and Jupiter to burst into western twilight dusk. Then draw an imaginary line from Jupiter and past Venus to locate Mercury near the sunset point on the horizon.
Mercury at its best, shining below Jupiter and Venus
Given an unobstructed horizon and clear sky, Mercury may become visible t othe unaided eye about 45 to 60 minutes after sunset. Binoculars, or any wide field optical aid, make the search for Mercury so much easier, especially if the sky is murky near the horizon – as is so often the case. Mercury is actually as bright as a first-magnitude star, but the glow of evening twilight tends to
subdue its brilliance. With Mercury setting a whopping 90 minutes after the sun at mid-northern latitudes, Mercury may well be yours to behold just before darkness falls in the first week of March.
Click here for the March 2012 guide to the five visible planets
http://earthsky.org/astronomy-essentials/visible-planets-tonight-mars-jupiter-venus-saturn-mercury.