By chance, I watched this weekend the last half of the movie "House of Cards"
http://us.imdb.com/Title?0107148
Some girl who's father died in an accident was told that he now lives on the Moon
(that reminds a little of the story about Apollo 14 astronaut Stu Roosa who visited Nepal and was asked by the kids about the Moon. He told them that it is dead and nothing is there. The children were pretty disturbed and later Roosa learnt, that the Nepalese believe that their dead ancestors live on the Moon) she becomes autistic and does strange things.
Her mother builds a tower (a spiral way leading upwards) like one her daughter built from cards.

Now the Bad Astronomy:
-One night, she stands in the center of the spiral and looking upwards, the full moon is directly above her.
It was too late in the movie that I could find out where it took place, but some internet sources say North Carolina. As I learnt from my Jules Verne, the Moon can be only in the zenith in Florida or Texas in the U.S. (I guess, when Verne wrote his book, Hawaii was not part of the U.S.)

-Sometimes, the Moon is a narrow crecent, but in the zenith and it is totally dark night. If the moon is a crescent, the angle to the Sun must be less than 90 degrees and when the Moon is in the zenith, the sun must be above the horizon and it can't be night.

-The diameter of the Moon is always much too large. The tower may be 30 or 40 meters high and the opening some 3 or 4 meters which roughly gives an opening angle of some 6 degrees, so the Moon would be just 1/12 of this. But in the movie it just fits into the opening with some border.

It's not clear in the movie if these scenes are "real" or just "dreams" or "phantasie",
so it also could be not Bad Astronomy but artistic license.

Harald



<font size=-1>[ This Message was edited by: kucharek on 2002-06-18 08:42 ]</font>

Depends on how close to the center of the spiral, and how straight up it is. Wilmington NC is only at lat. 34, and the moon orbit has an inclination to the ecliptic of more than 5 degrees, so in certain years, a full moon could be more than 84 (90 - 34.25 + 23.45 + 5.15) degrees above the horizon, or less than 6 degrees from the zenith. So she could just move 3 or 4 meters (your calculation) from the center, and the moon would be centered.

'Course, that's only in December. Did the movie occur in the Summer?

If you grow up in the Northern Hemisphere, the Moon looks upside down to you in the Southern Hemisphere. (I realize it's perception so no BA answers about a sphere please.) It was a very odd experience.

From the 45th parallel, I can't remember ever seeing the Moon directly overhead, day or night. But now of course, I'll have to observe for this feature.

Doh. Thanks Grapes. Even though I should have known better, I always pictured the Moon varying by about 5&deg; from the equator. But your calculation made me realize the variation is from the ecliptic and you also have to take the Earth's axial tilt into consideration.

So it's possible for the Moon to be seen directly overhead in a zone 23.45 + 5.15 = 28.6&deg; north or south of the equator. beyond that, it will never get that high in the sky.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

Yep. But that is still only theoretical. That 5.15 is actually a range from 5.15 to negative 5.15, which varies on an 18.6 year cycle--and the 23.45 maximum is only in December, when the Sun is at its own minimum. Those have to coincide to get the maximum, at a full moon. I think the next time we get close is Dec. 24, 2007

Just noticed that Mars (at -1.6, 16 arcmin. wide) rises very close to the moon on that night, 12/24/2007. That should be a pretty Xmas eve sight.

Uh, I always forget how much south the US is...
And the movie didn't take place in December, as some people slept outside without sleeping bags/tents or similar stuff, just a blanket (or how warm are NC winters?).

Harald

PS: Sorry for the match on friday. The Germans had the usual luck when playing bad. All 80 million national team trainers we have here in Germany agreed that the Germans played pretty bad and the US would have been a more worthy winner. Without Oliver Kahn - who was born and started his career in Karlsruhe where I live - the World Cup would already have been finished for the Germans. The thing that keeps the team going is, they are all pretty much afraid of the wrath of Kahn [img]/phpBB/images/smiles/icon_wink.gif[/img]
As Beckenbauer said: If you put the whole team - except Kahn - into a sack and beat it, you always hit one who deserves it.

In the summer, the moon is low--opposite the sun--so it would lose as much as 2 times 23.45 degrees elevation, and be quite low--but 40 degrees is still perceived as fairly high.

Thanks for the World Cup sentiments. Tough match.

If I may quote Captain Kirk from Star Trek II, it sums up my feelings about the US-Germany World Cup match.

"KAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHN!" - Captain Kirk

[img]/phpBB/images/smiles/icon_smile.gif[/img]

Rob