Re: [tdog] Total Lunar Eclipse
tdog wrote:
I have no clue what it means other than, it seems like a cool time to jump at
the instant of mid-totality:
In reply to:
At the instant of mid-totality (03:37 GMT), the Moon will lie in the zenith for observers in French Guiana. At this time, the umbral eclipse magnitude peaks at 1.1062.
The eclipse occurs when the moon passes through the earth's shadow (or, thought of another way, when the Earth passes between the moon and the sun). This happens at a specific time, everyone who is able to see the eclipse will see it at the same time.
Anyone located in the vicinity of the moon (most likely, on the Earth, but I suppose you could be in a space station and watch from there) can watch this event. But if you are on one side of the Earth, it might be early evening, and simultaneously on the other side of the Earth it might be after midnight or getting on toward dawn. If you were in New Zealand, it was still daytime, so the sun hadn't set and the moon hadn't risen.
So for some people, the moon was lower in the sky, and for others it was higher. If you wanted to see the moon *right overhead* (at the "zenith") you had to go to French Guiana, a (relatively) small country north of Brazil. A person there would actually be standing on the line connecting the centres of the Sun, Earth and moon. So then there would be *four* objects lined up: Sun, Earth, YOU, and the moon.
The "umbral magnitude" is a measure of the brightness ("magnitude") of the surface of the moon lying in the Earth's shadow ("umbra"). I'd have to google to find out exactly how such a thing would be reckoned, but according to the usual meaning of "magnitude", 1.1 would be the brightness of a bright star (and much, much dimmer than the moon usually appears).
Gotta check the weather for tomorrow... Maybe on a ladder?