February 2001

By Steve Stefanik

This month five planets will be visible with just your eyes. These are the same five planets that our forefathers saw wandering across the sky many millennia ago which inspired our imagination and began our quest for answers to the workings of the universe.

The planet Venus is the first of the five to appear as soon as the sun sets. You can’t possibly miss it blazing high in the southwestern sky at magnitude –4.5. Having reached greatest elongation (furthest separation from the sun) on January 16^th it will begin its descent toward the western horizon during the month. However, it still remains visible for threes hours before setting and does not reach its brightest until the 21^st although it will be lower in the western sky by month’s end.

The second planet is Mercury although it is considerably more difficult to spot and you won’t have many days to do so before it reaches inferior conjunction (passes between the earth and the sun) and becomes lost in the glare of the sun on the 13^th. Your best chance of getting a glimpse of this elusive planet is to scan the southwestern horizon with binoculars after the sun sets among the dim stars of the constellation Capricorn.

The third and fourth planets are Jupiter and Saturn, which are high overhead in the constellation Taurus the bull. The pair has been inseparable throughout the fall and winter leading the procession of familiar wintertime constellation Orion, Canis Major, Canis Minor, and Gemini.

Jupiter is the brighter of the two at –2.5 magnitude although it will fade by 2 tenths by the end of the month. Although it is past opposition it is still big enough and bright enough to provide hours of entertainment with a telescope as many of its ever-changing features rotate into and out of view during its 9 hour 50 minute rotation period. You can actually see its four largest moons change position in a matter of minutes.

Saturn is considerably dimmer because it is almost twice the distance of Jupiter from the sun but is still respectable at 0.1 magnitude. Even the smallest of telescopes or binoculars will reveal its rings which are tilted 23 degrees revealing an excellent view of its southern hemisphere.

The last of the five planets to make it into the night-time sky is Mars. It rises after mid-night among the stars of the constellation Libra in the east. Currently the distance between Earth and Mars is more than 111 million miles but as each day passes we are closing the gap in our shorter faster inside orbit so that by June when Mars reaches opposition (directly opposite the sun from us) it will be a mere 42 million miles. Presently it is magnitude +1.0 but by month’s end it will brighten to +0.5.