RE: [PSUBS-MAILIST] Portholes, Windows

[Ray Keefer <psubs2001@yahoo.com>]

Hi,

The effect is called Snell's Law. As light goes from
one medium to another it bends. Looking through a view
port you are going from air -> plexiglass (acrylic) ->
water.

Do a google on Snell's Law and you will find a lot of
details and formulas.

Regards,
Ray

--- Todd Fee <TFee@exhibitworks.com> wrote:

> George you got me thinking about sub windows today
> and specifically how
> light is bent while traveling through them. It seems
> to me that when I
> look in to a fish tank with flat glass windows or
> through the surface of
> a calm pond that the light is bent as it travels
> through to the denser
> medium. I'm sure there is some simple formula or
> explanation for this
> effect but I'd like to know how the effect works
> while traveling through
> a domed window or through a tube. I've seen plenty
> of spherical
> submarine windows but I have never been inside a
> submarine to know what
> it might look like looking outside in to the water
> from the interior of
> a spherical or domed window. I've seen the
> distortion caused when trying
> to look inside a submarine from the outside and I'm
> wondering if the
> effect is reversible or if while looking out the
> window, the effect is
> diminished. Is the image looking out similar to
> wearing a face mask
> while snorkeling, that is, is it enlarged? I
> remember snorkeling once
> and finding a $20 floating in the water and thinking
> it looked fake due
> to it's large size but when I returned to the
> surface and looked at it
> without the mask on I discovered to my great joy
> that it was real. How
> does a flat pane of glass enlarge an image? Perhaps
> someone in the group
> can direct me to a website detailing this
> phenomenon.\
> Perhaps I am missing something.
> Thanks
> Todd
>  
> George, this may also help you develop a lens for
> your camera that won't
> distort images. If you can develop a lens that would
> bring images back
> in to proper perspective you could have it cut on a
> cnc lathe and then
> polish it yourself. Perhaps you aren't concerned
> with this.
> 
> ________________________________
> 
> From: owner-personal_submersibles@psubs.org
> [mailto:owner-personal_submersibles@psubs.org] On
> Behalf Of George
> Slaterpryce
> Sent: Tuesday, February 28, 2006 9:38 AM
> To: personal_submersibles@psubs.org
> Subject: [PSUBS-MAILIST] Portholes, Windows
> 
> 
> I've been trying to make windows for my ROV's camera
> to look out of, I'm
> using acrylic and am pouring that into a mold for
> the window shape. The
> window is 2cm in diameter and 2mm thick. I need to
> keep it thin or it
> distorts the camera image. It's also flat, no dome
> shape (I couldn't
> figure out how to get a nice smooth dome... although
> now I have quite
> the collection of odd shaped tiddly winks if
> anyone's interested)
> Problem is the things are so brittle I don't think
> they'll stand up to
> much preasure. 
>  
> Am I missing something here?
> 


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 



************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of
our server receiving your request.

PSUBS.ORG
PO Box 311
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************