Mars is zooming in for a close approach to Earth tonight, offering backyard astronomers their best views of the red planet until 2014.
For the past few months Mars has appeared at night as a ruddy, starlike beacon rising in the east.
Tonight Mars will pass within 61 million miles (98 million kilometers) of Earth—close enough for well-equipped sky-watchers to make out details on the Martian surface.
"With a small telescope of about 6 inches (15.2 centimeters), the polar ice caps and other surface features are visible," said Raminder Singh, staff astronomer at the H.R. MacMillan Space Centre in Vancouver, British Columbia.
"Even a pair of binoculars will show it as a disk, as opposed to a star, which looks like a pinpoint of light."
And on January 29 Mars will reach opposition, which means it will rise in the east just as the sun sets in the west, making the red planet visible all night long.
"When opposition occurs, Mars is on the opposite side [of Earth] from the sun. If viewed from above the solar system, the sun, Earth, and Mars would be in a straight path," Singh said.
(Find out what happens when Mars is on the opposite side of the sun from Earth, aka in solar conjunction.)
Adding to the cosmic spectacle, on the night of opposition Mars will appear fairly close to the full moon, and the pair will glide together across the sky.
Mars Easy to See
The exact distance between Mars and Earth changes over time, because the orbits of the planets are not perfect circles, but elongated ellipses.
This orbital setup means Mars makes a close pass by Earth roughly every two years.
In August 2003 Mars made its closest pass by Earth in 60,000 years, swinging by at a mere 35 million miles (56 million kilometers) away. That event created spectacular views for astronomers but also seems to have spawned the recurring "Mars Spectacular" email hoax.
Tonight's approach won't be a particularly close pass. Still, the "flyby" will highlight how easy it is to spot Mars even with the naked eye, Singh noted.
"It's the third brightest object in the night sky, aside from the moon and the star Sirius," Singh said.
"People should really go outside and look at it, as it's an easy thing to see in the sky."