The planet Mercury left the evening sky to enter the morning sky on June 19, 2014. Even so, as mid-July approaches, Mercury is only now getting far enough from the rising sun to become visible in the morning sky. Find an unobstructed eastern horizon, and start your Mercury search about 75 minutes before sunrise if you live at mid-northern latitudes, or about 90 minutes before sunup if you live in the Southern Hemisphere.
Fortunately, you can use super-brilliant Venus, the second planet outward from the sun, to help you locate Mercury, the innermost planet of the solar system. Given a clear sky, Mercury might be yours to behold as darkness begins to give way to dawn.
At present, Mercury is about as bright as Aldebaran, the brightest star in the constellation Taurus the Bull. However, Mercury sits closer to the horizon and in the murkiness of twilight, so this world will probably be the harder of these two luminaries to spot in the morning sky. Binoculars may be helpful for your Mercury search.
Don’t fret too much if you miss Mercury on July 11. Mercury will brighten throughout the rest of the month of July 2014. Around July 20, Mercury will appear about three times brighter than it does at present. That’s in spite of the fact that Mercury is moving farther and farther away from Earth daily until it leaves the morning sky to enter the evening sky on August 8, 2014. After that, Mercury will come closer to Earth in the evening sky, until passing back into the morning sky on October 16, 2014.
Mercury is an unusual planet, in the respect that it’s brighter in our sky when it’s farther away but fainter when it’s closer. When Mercury lies farther distant, a greater portion of Mercury’s disk is illuminated by sunshine, which more than makes up for Mercury’s greater distance from Earth. At present, on July 10, Mercury’s disk is about 30% covered over in sunshine but will become about 60% illuminated in sunshine in another 10 days, or around July 20.
Although you can’t see the phases of Mercury without a telescope, you might discern Mercury’s change in brightness with binoculars or the unaided eye.
Bottom line: Watch for Mercury low in the east, and beneath the dazzling planet Venus, as darkness gives way to dawn from around July 11 through late July, 2014.