(Caption: On May 6, Earth has a ringside seat as Mercury, Venus, Mars and Saturn line up in their orbits, with Jupiter higher up in the night sky. This diagram shows how the lineup would look from a vantage point high above the ecliptic plane in which the planets' orbits lie.)
for sky show
a quartet of worlds
in post-sunset skies
By Joe Rao
April 26 — We are yet another week closer to the climax of the Great Planet Alignment of 2002, and now the final element of the mix is in place.
During the past couple of weeks, skywatchers around the world have been observing the western evening sky soon after sundown, as four naked-eye planets — Venus, Mars, Saturn and Jupiter — have stretched out in a long line. The line has slowly contracted each night, as the four planets draw closer to each other.
Even the moon got involved, closely passing each of the four planets over a span of five nights in mid-April.
Now through the first days of May will likely be the best time to see yet a fifth planet: Mercury.
Mercury has actually been visible for the past week, shining nearly as bright as Sirius, the brightest star in the sky, and setting nearly an hour after the sun.
Somewhat challenging to spot because it has been so near the horizon, Mercury has been getting progressively higher every evening.
This week, using the incredibly bright Venus as a guide, search the area of the sky below and to the right of Venus about a half-hour after sunset. Using binoculars, watch as Mercury passes just more than 1.5 degree south of the Pleiades star cluster on April 29. Each night, Mercury will appear a bit dimmer, but still at least as bright as a zero-magnitude star — easily visible to the unaided eye even under bright city lights.
Despite its low altitude, Mercury should be readily visible, hovering above the western horizon. Meanwhile, higher up, Venus, Mars and Saturn will be grouping into a striking and eye-catching array known as a “trio” by the early part of May.
Check back next Friday for a viewer’s guide to the May 5-6 climax of the Great Planet Alignment.
Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.
Should be a treat for those of you who like star/planet-gazing