Post by Centaur on Nov 9, 2006 0:15:54 GMT -6
Saturn has now become a Midnight Star, i.e. rising before Local Midnight (midway between sunset and sunrise) for those of us at mid-northern latitudes. This should make it easier for more of us to observe the ringed beauty of the heavens. It will continue to rise about four minutes earlier each evening. Saturn’s 2006-07 apparition occurs in a region of Leo with few naked-eye stars, although it will approach within 5° of Regulus on DEC 05 before it begins its retrograde motion. Its rings are now tilted about half as much as at the maximum in 2003. I’ve created a graphic demonstrating Saturn’s 2006-07 retrograde loop in ecliptical coordinates. It can be seen at www.curtrenz.com/astronomical.html
Saturn was in Conjunction behind the Sun on 2006 AUG 07. I calculate that it will reach its Western Quadrature (90° elongation from the Sun) on NOV 17 at 5:58 UT. It will then be rising around local midnight for observers in the tropics and somewhat earlier for those of us further north. Saturn will become stationary in celestial longitude and begin its apparent Retrograde motion on DEC 06 at 04 hr UT.
The following are my predictions of oppositional extremes during Saturn’s current Synodic Cycle (the period for Earth lapping Saturn: 1.035 years.) I estimate that Saturn will achieve its Greatest Brilliance at magnitude 0.0 on 2007 FEB 06 at 04 hr UT. That is similar to the magnitude of Arcturus, the brightest star in the northern celestial hemisphere. Saturns's Closest Approach to Earth of 8.20035 AU will come on FEB 10 at 15 hr UT. Shortly thereafter it will achieve all three types of Opposition:
FEB 10 at 18:42 UT: Opposition in Celestial Longitude
FEB 10 at 19 hr UT: Greatest Elongation of 178.7°
FEB 11 at 04:30 UT: Opposition in Right Ascension
Around the time of Opposition, Saturn will be rising near sunset, transiting the southern meridian around local midnight, and setting near sunrise. Its ecliptical latitude at that time will be N 1.3°, and its declination will be N 15.5°. That means for northern hemisphere observers, at meridian transit Saturn will culminate at an altitude that is equivalent to one’s co-latitude (90° minus one’s geographic latitude) plus 15.5°. For example, I live at N 42°, therefore it will culminate at 63.5° above my horizon.
At Opposition, Saturn’s apparent equatorial angular diameter will be 20.2 arcseconds and its rings will cover 45.8 arcseconds. Its axial Tilt relative to Earth will be –13.9°. That means we will still be viewing the southern side of its rings, which orbit above its equator. The Tilt will reach its extreme of –15.4° for this Synodic Cycle on APR 18. The extreme Tilt for its 29.5-year Orbital Cycle came in 2003 at -27.0°. The rings will seem to disappear around the period when Earth moves through Saturn’s equatorial/ring plane on 2009 SEP 04.
After Saturn’s 2007 Opposition, it will again become stationary in celestial longitude and resume its apparent Direct motion on APR 19 at 22 hr UT. It will reach Eastern Quadrature on MAY 09 at 12:05 UT. It will then be setting around local midnight for observers in the tropics and somewhat later for observers further north. Eventually it will again move in Conjunction behind the Sun on AUG 21.
Saturn presents a marvelous image in even a small telescope. Those who observe it for the first time are often thrilled. As a 12-year-old in 1958, I “discovered” Saturn when I aimed my new “Moonscope” at a pair of equally bright stars in Scorpius, where my star map showed only Antares should have been. After my own initial excitement, my brothers and neighborhood friends became awestruck when I allowed them views.
For alerts regarding the viewing seasons of the naked-eye planets, you may want to download my monthly astronomical calendar. Many use it as their computer’s desktop background wallpaper.
Let’s all enjoy the 2006-07 apparition of Saturn.
Saturn was in Conjunction behind the Sun on 2006 AUG 07. I calculate that it will reach its Western Quadrature (90° elongation from the Sun) on NOV 17 at 5:58 UT. It will then be rising around local midnight for observers in the tropics and somewhat earlier for those of us further north. Saturn will become stationary in celestial longitude and begin its apparent Retrograde motion on DEC 06 at 04 hr UT.
The following are my predictions of oppositional extremes during Saturn’s current Synodic Cycle (the period for Earth lapping Saturn: 1.035 years.) I estimate that Saturn will achieve its Greatest Brilliance at magnitude 0.0 on 2007 FEB 06 at 04 hr UT. That is similar to the magnitude of Arcturus, the brightest star in the northern celestial hemisphere. Saturns's Closest Approach to Earth of 8.20035 AU will come on FEB 10 at 15 hr UT. Shortly thereafter it will achieve all three types of Opposition:
FEB 10 at 18:42 UT: Opposition in Celestial Longitude
FEB 10 at 19 hr UT: Greatest Elongation of 178.7°
FEB 11 at 04:30 UT: Opposition in Right Ascension
Around the time of Opposition, Saturn will be rising near sunset, transiting the southern meridian around local midnight, and setting near sunrise. Its ecliptical latitude at that time will be N 1.3°, and its declination will be N 15.5°. That means for northern hemisphere observers, at meridian transit Saturn will culminate at an altitude that is equivalent to one’s co-latitude (90° minus one’s geographic latitude) plus 15.5°. For example, I live at N 42°, therefore it will culminate at 63.5° above my horizon.
At Opposition, Saturn’s apparent equatorial angular diameter will be 20.2 arcseconds and its rings will cover 45.8 arcseconds. Its axial Tilt relative to Earth will be –13.9°. That means we will still be viewing the southern side of its rings, which orbit above its equator. The Tilt will reach its extreme of –15.4° for this Synodic Cycle on APR 18. The extreme Tilt for its 29.5-year Orbital Cycle came in 2003 at -27.0°. The rings will seem to disappear around the period when Earth moves through Saturn’s equatorial/ring plane on 2009 SEP 04.
After Saturn’s 2007 Opposition, it will again become stationary in celestial longitude and resume its apparent Direct motion on APR 19 at 22 hr UT. It will reach Eastern Quadrature on MAY 09 at 12:05 UT. It will then be setting around local midnight for observers in the tropics and somewhat later for observers further north. Eventually it will again move in Conjunction behind the Sun on AUG 21.
Saturn presents a marvelous image in even a small telescope. Those who observe it for the first time are often thrilled. As a 12-year-old in 1958, I “discovered” Saturn when I aimed my new “Moonscope” at a pair of equally bright stars in Scorpius, where my star map showed only Antares should have been. After my own initial excitement, my brothers and neighborhood friends became awestruck when I allowed them views.
For alerts regarding the viewing seasons of the naked-eye planets, you may want to download my monthly astronomical calendar. Many use it as their computer’s desktop background wallpaper.
Let’s all enjoy the 2006-07 apparition of Saturn.
