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Saturn occults 8.4mag star - 5.00am this Saturday morning.

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20 years 3 months ago #1115 by michaeloconnell
Times below refer to the US. This will be best seen from 5.00am onwards this coming Saturday morning 15-Nov-'03. Click on link below for a good chart.


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This Is SKY & TELESCOPE's AstroAlert for Planetary Activity
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Late Friday night, November 14-15, Saturn and its ring system will glide
right in front of an 8.4-magnitude star in Gemini. Observers with large
enough telescopes -- ideally 8-inch or larger -- can watch in fascination
as the star leisurely fades in and out of view behind the various rings,
gaps, and the open space between the rings and the ball of Saturn itself.

For a diagram of the star's apparent path behind Saturn and the rings,
visit SkyandTelescope.com and click Observing Highlights. Or just click on
this link:

SkyandTelescope.com/observing/objects/oc...s/article_1102_1.asp

Skywatchers with the best view of this rare event are those living in
western North America. They'll be able to see the star enter the ring
system Friday evening and finally leave it 7 hours later.

For eastern North America and most of South America, Saturn is higher in
the sky during the initial stages; the star should reach the Cassini
Division in the rings shortly before 1 a.m. Eastern Standard Time. These
viewers can see the star coast right up to the planet's limb around 2 a.m.
EST, but dawn will hamper attempts to see it come out the other side.

European observers are limited to watching the star just enter the ring
system as morning twilight interferes.

What size telescope will be needed? SKY & TELESCOPE contributing editor
Thomas A. Dobbins notes that two British amateurs witnessed a similar
occultation of a 7th-magnitude star in 1917. Using 5-inch and 9-inch
telescopes, they could dimly see the star behind the outer ring (ring A),
making that ring seem translucent. But they failed to see the star when it
was behind the brighter B ring.

This week's event involves a slightly fainter star than the one observed in
1917. But the undersigned, on July 22-23, 1962, successfully observed
Saturn occulting an 8.6-magnitude star; I was using a 6-inch reflector in
New Jersey. Still, an 8- to 12-inch telescope will surely give a better view.

David W. Dunham of the International Occultation Timing Association has
this advice for observers: "The brightness of the rings and of Saturn will
make observation of this event (monitoring changes in the star's brightness
as it passes behind the rings) quite difficult, but the star should be
visible in Cassini's gap, and possibly though the thin inner C ring, with
medium-sized telescopes. For Washington, DC, the star will disappear at the
edge of the A ring at 5:27 UT (it may flicker as the thin F-ring briefly
covers it a minute or so before), then will appear in Cassini's gap at
5:53, and will traverse the C-ring from 6:38 to 7:02 (when it will
disappear into the atmosphere of Saturn). It will reappear from behind the
edge of Saturn at 10:31."

Roger W. Sinnott
Senior Editor
SKY & TELESCOPE

PS: Just one day before it encounters Saturn this week, the same
8.4-magnitude star will be occulted by Titan, Saturn's largest moon. Bruno
Sicardy (Paris Observatory) describes this event on his Web site:

despa.obspm.fr/%7Esicardy/titan/titan.html

He points out that it may produce a "central flash" around 0:13 Universal
Time on November 14th. Most likely to be seen from parts of South Africa,
and lasting up to 10 seconds, the flash is a visible focusing of the star's
light by Titan's atmosphere.

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