Note to Editors/Producers: This release is accompanied by three
publication-quality graphics; see details below, or go straight to the
online version of this release at

The Moon sweeps across the planet Saturn on Wednesday, February 20th, for
skygazers in North America. The rendezvous occurs in early-evening darkness
in the northeastern part of the continent, where it will be visible with or
without optical aid (weather permitting). Farther south and west Saturn and
the Moon meet in twilight or daylight; in these parts observers should be
able to catch the action in small telescopes.

Astronomers call this type of event, when one celestial object blocks
another from view, an occultation. Wednesday’s occultation happens when the
Moon, in orbit around the Earth, crosses the same part of the sky as
Saturn, which orbits the Sun. Their meeting is, of course, an illusion. The
Moon lies some 388,000 kilometers (241,000 miles) from Earth, while Saturn,
1.3 billion kilometers (830 million miles) away on February 20th, is
thousands of times more distant.

The Moon is a bit past first quaaily, 55 percent illuminated, when it
overtakes the ringed planet. By then the two will have already set in
Europe on the morning of the 21st, except for portions of Portugal, Spain,
and northwest Africa. But for the eastern United States and the northern
Caribbean, Saturn disappears behind the Moon’s dark limb (edge) when well
up in the south after sunset. It reappears on the bright limb roughly 60 to
75 minutes later. SKY & TELESCOPE has prepared a table listing when Saturn
disappears and reappears as seen from 300 North American cities:

The Moon takes roughly two minutes to swallow Saturn from ring tip to ring
tip. The event’s leisurely pace, combined with the rings’ tilt nearly wide
open as seen from Earth, means telescopic observers have a rare opportunity
to see or photograph the planet’s faint C (inner) and F (outer) rings.
Titan, the Saturn’s largest moon, trails the planet’s disappearance by 6 to
8 minutes, depending on your location. Because of its size, Titan should
make a gradual, 2-second-long entry behind the lunar limb.

Lunar occultations of bright planets are satisfying visual treats no matter
what equipment you use to observe them. Wednesday’s event occurs with the
Moon and Saturn nestled between the Hyades and Pleiades star clusters in
the constellation Taurus, the Bull, providing an attractive setting for
naked-eye or binocular viewing. To see a map of this heavenly get-together,
use SKY & TELESCOPE’s new interactive sky chart, which can be customized
for any location and any date and time:

The Moon will occult Saturn several more times this year, but these
cover-ups will be invisible or unfavorable for North Americans. The next
series of Saturn occultations does not begin until late 2006, so take in
Wednesday’s event if you have the good fortune of clear skies that evening.

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SKY & TELESCOPE is pleased to make several publication-quality graphics
available to help the news media explain this week’s lunar occultation of
Saturn to the public. Permission is granted for one-time, nonexclusive use
in print and broadcast media, as long as appropriate credit is given to SKY
& TELESCOPE and, for the photo, to Etienne Bonduelle. Captions are provided

Map of occultation visibilty across North America:

The lunar occultation of Saturn on February 20th favors the East Coast of
North America, where it occurs in darkness. Observers farther west will be
hampered by twilight or daylight but should still be able to see the planet
telescopically near the time of its disappearance. Purple curves give the
Universal Times of Saturn’s disappearance, red curves its reappearance. SKY
& TELESCOPE diagram.

Diagram showing path of Saturn behind the Moon as seen from various cities:

Skywatchers in many North American cities are poised to see the Moon occult
Saturn on February 20th, when the planet takes various paths behind the
lunar disk. Celestial north is up. SKY & TELESCOPE diagram.

Photo of Saturn emerging from a lunar occultation last November 3rd:

Observing from Cambrai in northern France, Etienne Bonduelle watched as
Saturn reappeared from behind the waning gibbous Moon on November 3, 2001.
He made this composite image using a Meade 8-inch LX90 Schmidt-Cassegrain
telescope and a Philips ToUcam Pro webcam.