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B Could church domes be used to project clouds on the floor?

  1. Dec 6, 2016 #1
    i read it in this book , check the page:

    in napolen funeral notredame dome was set a right lens oculus to project the clouds around napoleons corpse

    https://books.google.es/books?id=F1...=onepage&q=camera obscura church dome&f=false

    so could be a church dome trully be used as a camera obscura to project the clouds on the ground of the church to give it a magical look?

    wouldnt it just be a question of setting a right lens in the oculus of the lens?
     
  2. jcsd
  3. Dec 6, 2016 #2

    Simon Bridge

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    Any enclosed space can be set up as a camera obscura.
    To get a good image of the sky on the floor, you set the floor-lens distance to the same as the focal length. Get a lens and give it a go.
     
  4. Dec 6, 2016 #3
    thanks a lot for confirming this fact :)

    what i wonder now is why theres no other reference on the web to the posibility of domes of acting as camera obscura if the right lens set in the oculus but that obscure book i linked

    it would be quite appropiate to project the clouds in a church with the aid of a dome, i would visit any church to walk on clouds in an ancient flight simulator
     
  5. Dec 6, 2016 #4

    CWatters

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    You might also need to black out other windows.
     
  6. Dec 6, 2016 #5

    sophiecentaur

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    Shame your shadow would be all over the floor. (And that of everyone else, too.)
     
  7. Dec 6, 2016 #6

    Simon Bridge

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    I used t do this every day as part of an undergrad teaching lab - "find the focal length". You can get quite a good image of the sky on a bright day even outside - though it can help to direct the image to a part-shaded area. On a cloudy day, we just used the lab ceiling lights.

    I imagine the "lying in state among the clouds" thing would look best when viewed from a mezzanine gallery which many domed churches have.
    If the surface colors were handled right, there would be a strong effect of lying in the clouds.

    I have had the "walking in the sky" vertigo swimming at night, under a clear sky, on mirror flat water.
    Ripples spoil it - but just stand still and the illusion of stars below me was very strong.
     
  8. Dec 6, 2016 #7

    rcgldr

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    When I was a kid there was a squared tunnel that led to a large aqueduct. The tunnel was over 15 feet tall, long and curved just enough that it was pitch black in the middle section. There was an access spot with a sewer top next to ladder rungs implanted into the wall. The near 1 inch hole in the sewer worked well enough to produce a clear image of the sky and a telephone pole on the floor with no lens.
     
  9. Dec 7, 2016 #8

    sophiecentaur

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    I remember a great chance 'pinhole camera' effect when there was a large image of the Sun on a wall, from a keyhole in a door at the top of the stairs, 15m away. Great view of some sunspots at the time. You have to savour these things when they occur and Physics makes its presence felt.
     
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