Friday, November 30, 2012

Jupiter post-opposition

Event Date: December 7th
Time: 5:00 PM/6:00 AM (same date)


Brief

   Jupiter is past opposition, and decently placed by nightfall, low in the east; it is above the horizon, and will be seen a little higher each day.  With a retrograde motion leading to it rising more than 4 minutes earlier each day, Jupiter now sets before the Sun rises.  It can be seen low in the west-southwest when at that point.  Since darkness at this time of year is over 14 hours at this time of year, that still gives us many hours to see the planet rise, transit and set.
   Below, we see Jupiter above the horizon shortly after the Sun sets.  The second image shows the planet setting while the sky remains dark before dawn.



click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   As shown in image one, the celestial gridlines tell us that Jupiter makes a large circle around the north celestial pole.  Although we don't really realize it, we can know by following the shape of the gridlines on either side it of it; they curve or "curl" upwards.  After Jupiter gets high enough, don't forget to try to look at the contrast through the belts and zones with a telescope.  By then, atmospheric pollution is not as big a problem, and a magnification of between 150-200x can show these bands: dark for the belts, light for the zones.  The lower the magnification, the better the contrast, for if you just want to see the difference in color.  However, if you want to see a more natural alternating of the two, try a more powerful telescope.  They are clouds of crystalizing ammonia, with the zones cooler and the belts warmer.

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