analemma.com has some nice pics, and discussion of this interesting phenom

Beautiful site! This one goes into my bookmarks. Thanks.

In the Tom Hanks movie Castaway, he marked the days on a cave wall based on where the sun hit the wall as it shines through a whole each morning. The pattern shown was a figure 8. I guess that would qualify as an instance of good astronomy in a Movie.

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Depends upon who you ask. The Internet Movie Database goofs page for Cast Away has gone back and forth on this issue. Currently, it calls Chuck's creation of the analemma a "factual error." It says "To create and use the figure-eight shaped plot (technically called an analemma) that Chuck uses as a calendar requires a way to tell time. Using local solar time (e.g., local noon) is not sufficient; you could create a straight-line plot that way, but not the analemma."

That's true enough, but if we assume that Chuck knew as much about astronomy as Tom Hanks seems to, then Chuck would be able to construct an artificial analemma as a calendar. In other words, he can't construct the analemma exactly without a watch, but he definitely could draw one exactly if he knew how.

IMDB doesn't seem to accept this explanation.

Amazing site. Tks.

I would like to remark that "Analemma" is also the designation of an ancient astronomical instrument, which projects the celestial sphere orthographically, through mobile horizons or cursors; a scale in shape of "8", which displays the declination and the Time Equation for any day of the year.

Maybe they did. It's not there now.

Having conversations with yourself?

That happens with those multiple-personality-dudes...

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Just an update, guys.

A conversation would be where GrapesOfWrath would answer back.

That's a good site, and another in my favourites is
http://www.perseus.gr/Astro-Tips-Analemma.htm

(Anthony Ayoimamitis website) click on links down near the bottom of the page for further pics.

Tom Hanks' character in Castaway may have needed an accurate timepiece to mark out the analemma, but I find it good to point it out for interest's sake.

We have an analemma thing happenning in our gargage here at home-there is a hole in the roof and we've been marking out the sun's position on the floor and up the wall of the garage since March. Every couple of weeks, when I think of it- at our local noon.
We can see the figure 8 starting to take shape now.
I thought it may be an interesting exercise for our young daughter, but I confess I like it,too.


edited to correct spelling
-Carmel

I don't think so. He could have just drawn it, given the upper and lower limits, if he'd known enough about astronomy.

To get the "figure 8", you need accurate time. Without it, all you get is a vertical line of dots marking the Sun's culmination!

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No, I can draw one right now--in the middle of the night--if you give me the top and bottom limits. That's what I meant--if you know enough astronomy, say as much as Tom Hanks, then you could construct an analemma to keep track of the calendar. It may not be accurate, as far as the actual analemma for the configuration of hole-in-rock, time-of-day, etc., but it could work.