No way is the moon done serving up delights. Tireless as ever even after a long slog through Earth’s shadow Monday night, it lifts our gaze to the planet Saturn tonight.
Look moon-ward after 11 o’clock tonight and bang – Saturn will be right in front of your nose. The two worlds are in conjunction this evening and paired up very close to one another in the southern sky.
Moonrise happens around 10 p.m. but I’d suggest you wait until after 11 to see them best. From most locations, the two will be only about a degree apart.
Glare made seeing Spica before last night’s eclipse challenging unless you covered the moon with your thumb. Saturn and the moon will be just as close tonight, but the moon’s slimmed and dimmed since full and Saturn’s brighter than Spica, so you should have no problem seeing them side by side.
Use the opportunity to point your telescope at the planet famous for its hula hoop act. Saturn will be brightest and closest for the year on May 10 when it reaches opposition. Just as with Mars and the other outer planets, opposition is the time when a planet lines up with Earth on the same side of the sun. This cozy familiarity brings the planet into bright view. 10x binoculars will reveal the planet’s oval shape (thanks to the extra added width of the rings), and a small telescope magnifying 40x will bring at least one ring into clear view.
Most skywatchers would agree that Saturn is most attractive when the rings are tilted near their maximum. During planet’s 29.5 year orbit around the sun, their inclination to Earth varies from 0 degrees (edge-on) to 27 degrees. This month we see the north face of the rings tilted near maximum at 21.7 degrees.
Open rings means you can spot Saturn’s biggest ring gap called Cassini’s Division more easily now than anytime in the past few years. Named after Giovanni Cassini, a Italian/French astronomer who discovered the division and four of Saturn’s moons back in 1675, this “clear zone” spans some 3,000 miles (4,800 km) and separates the bright, wide B Ring from the narrower A Ring.
Spacecraft like NASA’s Cassini probe, which has been orbiting and studying the planet since 2004, have revealed that the gap isn’t as vacant as it appears. As far back as 1980, the Voyager 1 probe showed that that Cassini’s Division contains material similar to that found in the less massive C Ring. It’s even organized into multiple concentric rings divided by yet finer gaps.
Wishing you a happy night.