PDA

View Full Version : 2011 Apparition of Saturn



Centaur
2011-Jan-06, 06:44 AM
A bright white storm in Saturn’s northern hemisphere has caught the attention of astronomers. Saturn at magnitude +0.7 is in Virgo and will reach western quadrature (90° from Sun) on 2011 JAN 07. At that time it will be rising around local midnight, and then about four minutes earlier each night. Its ring tilt is generally improving compared with the last couple of years and is currently +10.2°. Saturn will commence apparent retrograde motion on JAN 26. Its greatest brilliance for this apparition should come around MAR 24 at magnitude +0.3.

Saturn’s oppositions are slowly moving into a warmer time of the year for observers north of the tropics. However, that also means its declination has begun dipping into the southern celestial hemisphere where it will remain until 2026. This year Saturn will achieve opposition from the Sun in ecliptical longitude on APR 03, along with its closest approach to Earth of this apparition at 8.6139 AU. On that date the tilt of its ring plane will be 8.7°, and its equatorial angular diameter will be 19.2 arcseconds. It will then be rising around sunset, transiting near local midnight, and setting as the Sun rises.

Apparent direct motion will resume on JUN 12, and eastern quadrature will be reached on JUL 02 Eventually Saturn will move to conjunction behind the Sun on OCT 13.

The only close conjunctions between Saturn and other planets during this apparition will occur in the glare of the Sun shortly before Saturn conjuncts with the Sun. On SEP 29 Venus will pass 1.3° south of Saturn, and on OCT 06 Mercury will pass 1.7° south of Saturn.

On JAN 24 Saturn will approach to 8.2° from magnitude +1.0 Spica before retrograde motion pulls it back. Saturn will not come close to any other first magnitude stars during this apparition.

The Moon will pass about 7° or 8° south of Saturn on JAN 24, FEB 21, MAR 20, APR 16, MAY 14, JUN 10, JUL 07, AUG 04, AUG 31 & SEP 28.

I’ve created several graphics related to Saturn and the changes in the tilt of its rings. They can be seen by clicking: http://www.curtrenz.com/astronomical and then going to the page for Superior Planets. (Please note than my website will soon be redesigned and you may have to go to a new Saturn page instead.)

Photos and descriptions of Saturn and its rings would be welcome additions to this thread