Now in the dim zodiacal constellation of Pisces, the Fishes, Mars is about 112 million miles (180 million kilometers) from Earth and shining at a magnitude 0.4. Thats just a trifle fainter than Procyon, the eighth brightest star in the sky.
Still, it is a tremendous come-down from last August, when Mars ranked as the third brightest object in the night sky, next to the Moon and Venus. In fact, this topaz-tinted world now only appears 1/20 as bright as it did 4- months ago.
Meanwhile, time is running out on your last chance to get a decent view.
Mars is farther from the Sun than is Earth, so it takes longer to make a complete orbit. Earth has passed Mars on an inner track and is racing away from the red planet.
By the end of February Mars will have receded to 154 million miles (247 million kilometers) from Earth and will have dimmed further to magnitude 1.1 (about as bright as the star Pollux in Gemini).
Mars is now rather disappointing in telescopes as its apparent diameter also shrinks. Its apparent size as seen through telescopes is only about 30 percent of what it was back in late August, just 7.7 arc seconds in width in astronomers' parlance.
Put another way: you would need an eyepiece that magnifies approximately 230 power to make Mars appear as large as the Moon does with your unaided eye. Most novice observers have small telescopes where such a magnification is not recommended because it would only serve to make the image appear rather dim and fuzzy.
Mars doesnt even appear as a full disk at the present time; the angle of illumination between Mars, Earth and Sun makes Mars appear more like a gibbous Moon, about 88 percent illuminated.
During the next several weeks, the red planet will be setting roughly between 11:30 p.m. and midnight. Although getting progressively dimmer, Mars will still do a pretty good job of staying well ahead of the Sun through about mid-spring. But toward the end of May it will begin sliding more rapidly toward the Suns vicinity, eventually setting before the end of evening twilight by the middle of June.
Along the way it will meet up with a couple of naked-eye planets.
In the last week of April Mars will appear to hover near dazzling Venus. By the third week of May it flirts with Saturn, and on the evening of May 22 it will form a loose triangle with Saturn and a lovely crescent Moon.
Mars will continue to fade as it gets farther away from the Earth through the balance of spring and into early summer. Finally, sometime during mid- or late-July it will become so deeply immersed in the bright evening twilight, so as to be rendered completely invisible. By then it will also be at its absolute faintest magnitude of +1.8, putting it in the rank of second-magnitude stars.
On Aug. 7 Mars will reach the aphelion part of its orbit, placing it at its greatest distance from the Sun: nearly 155 million miles (249 million kilometers).
advertisement
