Re: Equatorial Ceilng Dial

2002-01-14 Thread Chris Lusby.Taylor 

If the mirror is sufficiently small, the reflected spot will appear to be a 
circle, but
it will actually be elliptic for low solar elevations. The hour and declination 
lines
will indeed be mirror images of those on a hemispherium.
BSS members who attended the meeting in Cirencester will recall Mark 
Lennox-Boyd's
description and model of a sundial very much like this, with a mirror and a 
curved
ceiling, that he was building in Italy. Does anyone know if it has been built 
yet?

Regards
Chris Lusby Taylor
51.4N 1.3W.

"fer j. de vries" wrote:

> Hi John,
>
> I have no idea if the reflected sunspot will be a circle or not.
> I should experiment with this to see what happens.
>
> In any case, assuming the mirror is in the center of the sphere, the
> reflected beam is perpendicular to the ceiling and it is rather easy to test
> this with a peace of cardboard.
>
> However, no sun to see this day.
>
> Fer.
>
> Fer J. de Vries
> ferdv+AEA-iae.nl
> http://www.iae.nl/users/ferdv/
> Eindhoven, Netherlands
> lat.  51:30 N  long.  5:30 E
>
> - Original Message -
> From: +ACI-John Carmichael+ACI- +ADw-johncarmichael+AEA-mindspring.com+AD4-
> To: +ACI-fer j. de vries+ACI- +ADw-ferdv+AEA-iae.nl+AD4-
> Cc: +ACI-Sundial List+ACI- +ADw-sundial+AEA-rrz.uni-koeln.de+AD4-
> Sent: Sunday, January 13, 2002 3:19 PM
> Subject: Equatorial Ceilng Dial
>
> +AD4- Hi Fer +ACY- others:
> +AD4-
> +AD4- Let's say you have a spherical room, built like a planetarium, where the
> +AD4- walls curve up into the ceiling and you locate your mirror in the 
> center.
> +AD4- (Actually, the room would be a quarter sphere, like an orange segment,
> with
> +AD4- one flat side being the floor, and the other flat side the southern wall
> +AD4- with the window with mirror).
> +AD4-
> +AD4- Would the sunspot be perfectly round all the time?  Also, what would the
> +AD4- hour and declination lines look like? (Like the lines on a 
> hemispherium?)
> +AD4- Would this be called an +ACI-Equatorial Ceiling Sundial+ACI-?
> +AD4-
> +AD4- John
> +AD4-
> +AD4- John L. Carmichael Jr.
> +AD4- Sundial Sculptures
> +AD4- 925 E. Foothills Dr.
> +AD4- Tucson Arizona 85718
> +AD4- USA
> +AD4-
> +AD4- Tel: 520-696-1709
> +AD4- Email: johncarmichael+AEA-mindspring.com
> +AD4- Website: +ADw-http://www.sundialsculptures.com+AD4-
> +AD4- - Original Message -
> +AD4- From: +ACI-fer j. de vries+ACI- +ADw-ferdv+AEA-iae.nl+AD4-
> +AD4- To: +ACI-sundial+ACI- +ADw-sundial+AEA-rrz.uni-koeln.de+AD4-
> +AD4- Sent: Friday, January 11, 2002 7:19 AM
> +AD4- Subject: Polar Ceing Dial
> +AD4-
> +AD4-
> +AD4- +AD4- Diallists,
> +AD4- +AD4-
> +AD4- +AD4- In my message of 2002-01-09 about the limits of a polar dial on a
> ceiling
> +AD4- I
> +AD4- +AD4- ended with:
> +AD4- +AD4-
> +AD4- +AD4- +ADw- Who has an inclined ceiling, higher at the south end?
> +AD4- +AD4- +ADw- Won't that be better?
> +AD4- +AD4-
> +AD4- +AD4- I wanted to know this for sure and I started with a ceiling with 
> an
> +AD4- +AD4- inclination of 160 degrees in stead of 180 degrees.
> +AD4- +AD4- A difference of 20 degrees as is shown in the attached picture.
> +AD4- +AD4-
> +AD4- +AD4- The mirror now gets an inclination of 0.5 ( phi - 20 ).
> +AD4- +AD4- For latitude 52 this is 16 degrees.
> +AD4- +AD4-
> +AD4- +AD4- The pattern on the now inclined ceiling also is a polar dial.
> +AD4- +AD4-
> +AD4- +AD4- I did not look for the extreme limits, but just gave it a chance.
> +AD4- +AD4-
> +AD4- +AD4- Following the same procedure the polar dial is cut off at about 
> 3.5
> hours
> +AD4- +AD4- before and after noon and it is seen that the mirror is less 
> inside.
> +AD4- +AD4- (distance CB ).
> +AD4- +AD4-
> +AD4- +AD4-  At the left the pattern for a south facing dial though CM with
> +AD4- (pin)gnomon
> +AD4- +AD4- CB is drawn.
> +AD4- +AD4-
> +AD4- +AD4- The mirror is at distance CM from C and that is shown with the 
> line KL.
> +AD4- +AD4-
> +AD4- +AD4- At summer solstice the mirror will be in the shadow of the edge 
> of the
> +AD4- +AD4- ceiling untill about 3.5 hours before noon and is shaded again 
> 3.5 hours
> +AD4- +AD4- after noon.
> +AD4- +AD4-
> +AD4- +AD4- So this configuration will work 7 hours at summer solstice.
> +AD4- +AD4- A great improvement compared with an horizontal ceiling.
> +AD4- +AD4-
> +AD4- +AD4- I only need to rebuild my house.
> +AD4- +AD4-
> +AD4- +AD4- Best wishes, Fer.
> +AD4- +AD4-
> +AD4- +AD4- Fer J. de Vries
> +AD4- +AD4- ferdv+AEA-iae.nl
> +AD4- +AD4- http://www.iae.nl/users/ferdv/
> +AD4- +AD4- Eindhoven, Netherlands
> +AD4- +AD4- lat.  51:30 N  long.  5:30 E
> +AD4- +AD4-
> +AD4- +AD4-
> +AD4- +AD4-
> +AD4- +AD4-
> +AD4- +AD4-
> +AD4- +AD4-
> +AD4-
> +AD4-

Re: Equatorial Ceilng Dial

2002-01-14 Thread fer j. de vries 

Hi John,

I have no idea if the reflected sunspot will be a circle or not.
I should experiment with this to see what happens.

In any case, assuming the mirror is in the center of the sphere, the
reflected beam is perpendicular to the ceiling and it is rather easy to test
this with a peace of cardboard.

However, no sun to see this day.

Fer.


Fer J. de Vries
[EMAIL PROTECTED]
http://www.iae.nl/users/ferdv/
Eindhoven, Netherlands
lat.  51:30 N  long.  5:30 E

- Original Message -
From: "John Carmichael" <[EMAIL PROTECTED]>
To: "fer j. de vries" <[EMAIL PROTECTED]>
Cc: "Sundial List" 
Sent: Sunday, January 13, 2002 3:19 PM
Subject: Equatorial Ceilng Dial


> Hi Fer & others:
>
> Let's say you have a spherical room, built like a planetarium, where the
> walls curve up into the ceiling and you locate your mirror in the center.
> (Actually, the room would be a quarter sphere, like an orange segment,
with
> one flat side being the floor, and the other flat side the southern wall
> with the window with mirror).
>
> Would the sunspot be perfectly round all the time?  Also, what would the
> hour and declination lines look like? (Like the lines on a hemispherium?)
> Would this be called an "Equatorial Ceiling Sundial"?
>
> John
>
> John L. Carmichael Jr.
> Sundial Sculptures
> 925 E. Foothills Dr.
> Tucson Arizona 85718
> USA
>
> Tel: 520-696-1709
> Email: [EMAIL PROTECTED]
> Website: 
> - Original Message -
> From: "fer j. de vries" <[EMAIL PROTECTED]>
> To: "sundial" 
> Sent: Friday, January 11, 2002 7:19 AM
> Subject: Polar Ceing Dial
>
>
> > Diallists,
> >
> > In my message of 2002-01-09 about the limits of a polar dial on a
ceiling
> I
> > ended with:
> >
> > < Who has an inclined ceiling, higher at the south end?
> > < Won't that be better?
> >
> > I wanted to know this for sure and I started with a ceiling with an
> > inclination of 160 degrees in stead of 180 degrees.
> > A difference of 20 degrees as is shown in the attached picture.
> >
> > The mirror now gets an inclination of 0.5 ( phi - 20 ).
> > For latitude 52 this is 16 degrees.
> >
> > The pattern on the now inclined ceiling also is a polar dial.
> >
> > I did not look for the extreme limits, but just gave it a chance.
> >
> > Following the same procedure the polar dial is cut off at about 3.5
hours
> > before and after noon and it is seen that the mirror is less inside.
> > (distance CB ).
> >
> >  At the left the pattern for a south facing dial though CM with
> (pin)gnomon
> > CB is drawn.
> >
> > The mirror is at distance CM from C and that is shown with the line KL.
> >
> > At summer solstice the mirror will be in the shadow of the edge of the
> > ceiling untill about 3.5 hours before noon and is shaded again 3.5 hours
> > after noon.
> >
> > So this configuration will work 7 hours at summer solstice.
> > A great improvement compared with an horizontal ceiling.
> >
> > I only need to rebuild my house.
> >
> > Best wishes, Fer.
> >
> > Fer J. de Vries
> > [EMAIL PROTECTED]
> > http://www.iae.nl/users/ferdv/
> > Eindhoven, Netherlands
> > lat.  51:30 N  long.  5:30 E
> >
> >
> >
> >
> >
> >
>
>

RE: Equatorial Ceilng Dial

2002-01-13 Thread Ian Maddocks 

Hi John,

-Original Message-
Let's say you have a spherical room, built like a planetarium, where the
walls curve up into the ceiling and you locate your mirror in the
center.
(Actually, the room would be a quarter sphere, like an orange segment,
with
one flat side being the floor, and the other flat side the southern wall
with the window with mirror).
Would the sunspot be perfectly round all the time?  Also, what would the
hour and declination lines look like? (Like the lines on a
hemispherium?)
Would this be called an "Equatorial Ceiling Sundial"?
- Original Message -

I believe what you're describing is rather like the Helios XXII
sculpture by Barry Mason, except he uses a pond rather than a mirror to
much more dramatic effect.
See  http://www.rbs.org.uk/cgi-bin/getMember.cgi?member=083
Barry gave a talk on his sun sculptures at the 2000 BSS annual meeting
2000.

Regards

Ian Maddocks