Event Date: December 15th
Time: 5:00 PM
Brief
Yesterday, I showed the Moon beginning to have an impressive apparition as a young waxing crescent; such a showing normally starts at the end of a year and the beginning of the next, with the Moon's orbit leading to some difference between it and the Sun's declination. As shown in the image yesterday and below, its orbit puts it north of the ecliptic, and helping give it a little extra "lift" north.
I will include both guidelines and the celestial equator once again. Our satellite, having waxed from 4% to 10% [illuminated] over the last 24 hours, sets almost exactly two hours after the Sun this evening.
 |
click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.
|
Detailed
As we see above, the Moon's orbit eventually takes it across the celestial equator, putting it there a little west of where our Sun crosses the equator at the celestial meridian (not shown). Therefore, not only is the Moon setting later by several more minutes after the Sun each day; it is spending more time in the sky altogether. For example, right now the Moon is where the Sun would be in mid-late January, when the days are still very short and the nights long. However, when the Moon crosses the equator, near the point of maximum ecliptic latitude shown towards the image's left side, it spends a little over 12 hours above the horizon. This is the case as seen just about everywhere in the world, except extreme latitudes at the poles, where the Sun, planets and Moon all barely hover above the horizon, or don't quite clear it; such depends on which pole one is viewing from in frigid conditions, and the declination of what (s)he is viewing.
No comments:
Post a Comment