View Full Version : Saturn's Apparition of 2007-08

2007-Nov-20, 07:39 PM
Saturn will soon be returning to our evening skies. It will begin rising before local midnight (the time midway between sunset and sunrise) for Chicagoland observers on 2007 NOV 24, making it both a midnight star and a morning star. That will be essentially true for most observers at mid-northern latitudes. In standard time Saturn began rising before midnight for Chicagoland on NOV 19.

Saturn will reach its western quadrature (90° from Sun) on NOV 30. It will begin apparent retrograde motion on DEC 19. Its greatest brilliance for this opposition should be achieved around 2008 FEB 16 at magnitude +0.2. Its closest approach of 8.2914 AU and its oppositions in longitude, right ascension and elongation will all occur on FEB 24 CST.

At the time of opposition the apparent tilt of Saturn’s rings (technically, the saturnocentric latitude of Earth) will be -8.4°. Its angular equatorial diameter will be 20.0 arcseconds. At a declination of N 11.3° Saturn remains well positioned in the sky for northern hemisphere observers.

Retrograde motion will end on MAR 02. Eastern quadrature will be achieved on MAY 22. Then on SEP 03 Saturn will be in conjunction with the Sun.

The southern side of Saturn’s rings was maximally exposed for us on 2003 APR 07 at 27.0°. The Sun will pass through the ring plane on 2009 AUG 10, then the Earth will do so on SEP 04. Between those dates the dark side of the rings will be presented to us, and they will be essentially invisible. Although that will be at a time when Saturn is nearing conjunction with the Sun.

Saturn's ring plane is not actually wobbling. It is the direction toward which we view the rings that changes as both the Earth and Saturn orbit the Sun.

Your photos and descriptions of Saturn would be welcome additions to this thread. :)

Below are two graphics that I’ve created. The first one demonstrates Saturn’s retrograde loop in equatorial coordinates during the current apparition. The second one shows the generally decreasing exposure of the rings in ecliptical coordinates from now through September of 2009.



2007-Nov-20, 08:14 PM
When Saturn's rings are seen edge-on, can they still be seen in a small telescope?

Kaptain K
2007-Nov-20, 08:20 PM
No! Not even through a large one!

2007-Nov-20, 08:23 PM
No! Not even through a large one!

Wow. How about the largest scopes?

BTW, How are you feeling?

2007-Nov-20, 08:40 PM
Concerning the rings seen edge-on, this is rather amusing (from wiki):

The rings were first observed by Galileo Galilei in 1610 with his telescope, but he was unable to identify them as such. He wrote to the Duke of Tuscany that "The planet Saturn is not alone, but is composed of three, which almost touch one another and never move nor change with respect to one another. They are arranged in a line parallel to the zodiac, and the middle one (Saturn itself) is about three times the size of the lateral ones [the edges of the rings]." He also described Saturn as having "ears." In 1612 the plane of the rings was oriented directly at the Earth and the rings appeared to vanish. Mystified, Galileo wondered, "Has Saturn swallowed his children?", referring to the myth of the god Saturn eating his own children to prevent them from overthrowing him. Then, in 1613, they reappeared again, further confusing Galileo.

Kaptain K
2007-Nov-20, 09:10 PM
Wow. How about the largest scopes?
I believe (in other words,don't quote me) that with some judicious processing, they would just be detectable with a very large pro scope.

BTW, How are you feeling?
Very well. Thanks for your concern. The surgeon is going to take out the staples and wound-drain next Monday! :clap::clap::clap: After that, all I have to do is get my strength and endurance back. I'll certainly have some interesting scars to explain at the swimming pool next summer! :whistle:

2007-Nov-20, 09:12 PM
Very well. thanks for your concern.


Centaur, sorry for the OT stuff.