Event Date: December 24th
Brief
Astronomy fans around the world will have a real treat this Christmas eve and tomorrow, as the big, waxing gibbous Moon approaches Jupiter. The separation shrinks by the hour. As shown below, I have included the orbits of both, as the Moon crossed descending node early this morning. The ecliptic as always, reminds us of the inclinations of the orbits. Unlike the Moon's orbit with the precession of the nodes every 18.6 years, Jupiter and the other planets' orbits don't change from year to year; if so, extremely slowly and unnoticeably.
 |
click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.
|
Detailed
At the time above, Jupiter and the Moon are still outside of most binocular fields of view. However, as the night progresses, the Moon moves about one diameter per hour from west to east. Knowing this, can you calculate how many hours it will take for the Moon to come closest to Jupiter? Remember that the difference in ecliptic latitudes will factor into how long it will take. Remember also, that Jupiter will moves very slightly in retrograde motion, albeit slowing down slightly each day. Although being as gradual as its movement is, I mainly bring this up as a reminder that Jupiter is all but staying still, waiting for the Moon to catch up with it. Give it a try, predicting hours and minutes and when I reveal the closest encounter tomorrow with the clock, find out if you are correct! Speaking of which, if I make this sound reasonably easy, it isn't, as I have as hard a problem as anyone predicting!
No comments:
Post a Comment