That is an excellent question! I have seen this photo before, and never
noticed the numbers running twice in a semicircle. I, too, am perplexed.
I read about this dial in Hester Higton's book "Sundials at Greenwich."
The dial operates on two successive polarizations of light - the first
being wh
Interesting dial. What is the purpose of the grid of white lines
surrounding the gnomon? -Bill
2015-04-13 8:47 GMT-04:00 Josef Pastor :
> Liebe Sonnenuhrenfreunde,
>
>
>
> die neue „Sterne und Weltraum“ Heft 5-2015, die ab morgen im gut
> sortierten Zeitschriftenhandel erhältlich sein wird, be
Awesome dial. I have never seen a gapped nodus like that before, not have
I seen the use of mirrors to project an image for when the sun is behind
the wall. Please tell us who designed this dial, and how it was
commissioned? I could not find that information in the article. I work
with mirror g
Brilliant. First dial I've seen like that. Thanks for sharing
-Bill
On Thu, Apr 23, 2015 at 8:24 AM, Richard B. Langley wrote:
> Came across this, this morning:
> http://www.instructables.com/id/Time-oclock-shadow/
> --Richard Langley
>
>
> --
Hello Ken,
I have tried some powder coating on aluminum with acceptable results.
1. I do not have any powder coating facilities. I bought small amounts of
powder coat on the internet (I don't recall where, but could look it up),
along with a small amount of a liquid solution that suspends the p
Well, if you are going to allow compass directions, then that opens the
door to all loxodromes. There are an infnite number of loxodromes that
connect two points on a sphere, if you allow loxodrome paths that travel
more than once around the globe! This gives an infinite number of compass
directi
Sundials.org is unavailable tonight. Anyone aware of a problem?
-Bill Gottesman
---
https://lists.uni-koeln.de/mailman/listinfo/sundial
Yay!
On Sun, Nov 1, 2015 at 9:53 PM, Jack Aubert wrote:
> Yes, the server died, but has been resurrected with some replacement
> hardware. It is back up and running now.
>
>
>
> Jack Aubert
>
>
>
> *From:* sundial [mailto:sundial-boun...@uni-koeln.de] *On Behal
Very cool. Has anyone had a chance to try the free 3D software OpenScad?
By the way, I am skeptical that the sundial can handle declinations near
the solstices.
-Bill
On Fri, Nov 6, 2015 at 7:39 AM, Darek Oczki wrote:
> Hello everyone
>
> Have you seen this 3D digital sundial?
> http://3dprint.
Thank you Frank! What a fun thing to know! -Bill
On Wed, Feb 24, 2016 at 3:11 AM, Frank King wrote:
> Dear All,
>
> As is my four-yearly custom, I wish readers of
> this list a Happy Leap Year Day.
>
> I was delighted, in 2012, when I sent out a
> similar greeting, that not a single reader
> q
Why is the Longyearbyen sundial irrelevant to your project?
- Bill
On Friday, July 22, 2016, Helmut Haase wrote:
> Hi all,
> When studying the wide polar gnomon one inevitably encounters edge changes
> to be respected. My special focus is on a horizontal dial for a location
> with midnight sun.
That was awesome, Bob.
-Bill
On Wed, Dec 21, 2016 at 8:43 AM, Robert Terwilliger
wrote:
> This is a good one!
>
>
>
> Traces of the Sun
>
> http://apod.nasa.gov/apod/ap161221.html
>
>
>
> Bob
>
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinf
Hello Ken,
Fantastic display. I hope you had fun and a lot of interested visitors.
-Bill
On Sat, May 6, 2017 at 8:15 AM, Kenneth R clark
wrote:
> I am not sure my post went through. Trying again.
>
> Hi everyone,
>
>
> I was invited back to the North Museum in Lancaster PA to do another
Hello Sundial Listers,
I was wondering if anyone of us knew John B Mclemore, the Horologist
protagonist of the This American Life radio show S-Town. The story
includes his fascination with sundials and astrolabes. Was he known to any
of us?
-Bill
Tony Moss described a secure and permanent mounting method using bolts
permanently fixed to the underside of the dial. The dial is then set in
mortar atop the pedestal, and the bolts become permanently fixed in the
mortar. Lord knows how this could be removed later.
Another method involved using
Not all brass/bronze is the same. I prefer silicon bronze. It is typical
for large outdoor sculptures, and also marine hardware and propellers. It
turns dark, not green, and is very durable. -Bill
On Sun, Jun 4, 2017 at 9:58 PM, rodwall1...@gmail.com wrote:
> Hi all,
>
> For a sundial that w
Another fabulous Fabio sundial! Clever and fun. -Bill
On Mon, Jun 5, 2017 at 5:03 AM, fabio.sav...@nonvedolora.it <
fabio.sav...@nonvedolora.it> wrote:
> Hi all
>
> I just finished to design an horizontal sundial adjustable for a range of
> latitude, in this case from 30° N to 50° N, I also buil
Lord knows how you came up with this. -Bill
On Fri, Jul 7, 2017 at 5:46 AM, fabio.sav...@nonvedolora.it <
fabio.sav...@nonvedolora.it> wrote:
> Hi, I just finished a work that has engaged me in the last two weeks.
>
> For those are interested about the Kepler's laws, it
>
> ---
> New Outlook Ex
Very topical for today.
How are those images generated? What are the different softwares involved?
-Bill
On Wed, Feb 14, 2018 at 4:55 AM, Reinhold Kriegler wrote:
>
>
> https://www.youtube.com/watch?v=mZBwBqIbwYw
>
> HAVE A LOOK AND ENJOY!
> A most charming idea by Gian Casalegno!
>
> Reinhol
um=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> Mail
> priva di virus. www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> <#m_-4867647885745656337_DAB4FAD8-2
I don't know any software, but my approach would be:
1. Use Altitude and Azimuth and Latitude to calculate Declination
(straightforwad Spherical Trig calculation. If you need formula, it will
take me a moment to come up with it)
2. Calculate dates for the declination (longitude/time zone will mat
Hello Kurt, Congratulations on completing a challenging project.
I would like to ask a few optical questions.
Why did you use a lens at all? In my experience, a lens differs from an
open aperture in that it distorts the path of the sun. For example,
straight lines, if they are off-axis, are proj
Hello Kurt,
Fun video. I'm sure the construction was harder than it looks.
Why are the indoor hour lines curved? How is this different from a
gnomonic projection, which has straight hour lines?
-Bill
On Sat, Apr 21, 2018 at 8:33 AM, Kurt Niel wrote:
> Hi All,
>
> just added two videos abou
Very nice, Ken. Graphics seem to be a perfect match and seem very
precise. Are they vinyl, or paint, or anodizing?
-Bill
2018-05-03 21:37 GMT-04:00 clarkkr--- via sundial :
> Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
> eigentliche Nachricht steht dadurch in einem Anha
Thought provoking video. Here are a two simple questions worth
contemplating:
1. From what perspective is the video filmed?Is the camera roughly south,
north, east,or west of the summer solstice mark?
2. Why does the sun appear elongated in its right-to-left direction of
travel across the scre
it my website about the sundials in the province of Limburg (Flanders)
> with a section 'worth knowing about sundials' (mostly in Dutch):
> http://www.wijzerweb.be
>
>
>
>
> Op 7-jun-2018, om 19:51 heeft Bill Gottesman het volgende geschreven:
>
> Thought provoking
Hello Claus,
Yes, in J. L. Heilbron's "The Sun in the Church" he reports that Toscanelli
designed the original meridian and solstice mark in 1510, placing a bronze
plaque at the sun's noon solstice image. Around 1754 Leonardo Ximenes
discovered that Toscanelli's 1510 meridian was off by almost a
The NASA page says the photos were taken at 4PM, but it sure looks like
they were taken at mean solar noon (because the analemma is vertical).
Does anyone have an explanation for this?
-Bill
On Sun, Sep 23, 2018 at 10:38 AM Robert Terwilliger
wrote:
> Astronomy Picture of the Day
>
>
>
> https:
;
> Steve
>
>
> On 2018-09-23 7:58 AM, Bill Gottesman wrote:
>
> The NASA page says the photos were taken at 4PM, but it sure looks like
> they were taken at mean solar noon (because the analemma is vertical).
> Does anyone have an explanation for this?
>
> -Bill
>
Hello Frank,
Could the space be a north-south alley, street, or park between two
buildings? The vertical sides of the buildings adjoining the space can be
seen as two vertical gnomons for an azimuthal dial. You would lay out the
morning hours to the west of the eastern building, and the afternoo
Link to photos did not work. Please check link. -Bill
On Thu, Jan 10, 2019 at 6:29 AM Azucena Hernandez <
azucena.hernandezpe...@gmail.com> wrote:
> Dear all,
>
> This is my first message to this mailing list and I do it under the
> suggestion of John Davis from the UK. My filed of research wit
strips had been labeled consecutively (from 6:00AM to 6:00 PM
for the semicircle).
-Bill Gottesman
On Tue, May 21, 2019 at 7:00 PM Patrick Vyvyan
wrote:
> Wheatstone's Polarizing Dial
>
> An explanation of Wheatstone's invention is to be found in the Report of
> the
Hello Steve, I'll take a guess at this.
I think the dial is really a heliochronometer with an analemma, not an
analemmatic dial. I think the screws up top held a focusing lens or a
pinhole aperture that projected a beam on to an analemma on to the lower
plate. The analemma is not visible in that
It's always nice when things work like you hope they will. Fun photo -Bill
On Tue, Sep 24, 2019 at 2:07 PM wrote:
> Hi All,
>
> We also celebrated Equinox in Wroclaw, Poland with a newly built noon mark
> dial - following the original, Leicester "Eye of Time" pattern by professor
> Allan Mills.
There is a much more detailed image of the mutli-purpose dial if you "look
inside" the book sample at
https://www.amazon.com/Time-Flies-Really-stands-still/dp/1977072658.
This would not function as a common horizontal sundial (except at the north
or south pole). If it were properly tilted and ori
I should add, it would be an extremely confusing way to teach sundials, and
I would not recommend this dial from a teaching standpoint.
-Bill
On Sat, Apr 3, 2021 at 3:13 PM Bill Gottesman
wrote:
> There is a much more detailed image of the mutli-purpose dial if you "look
> insid
My two cents:
I have a different guess about the round dial with the indicator. My guess
is that it is a calendar of months, and that turning the indicator to the
correct month adjusts the length of the adelaide to the correct distance
for reading time on the azimuth dial. I do not know what cast
the adelaide, I think
the whole center section (curcular brass plates) pivots along with the
adelaide, so that is moot.
-Bill again.
On Fri, Oct 29, 2021 at 9:24 PM Bill Gottesman
wrote:
> My two cents:
> I have a different guess about the round dial with the indicator. My
> guess is tha
I'm pretty sure that for excel, you would need to enter
=LOG(TAN(RADIANS(7)))
because the trig functions in excel work on radians rather than degrees.
-Bill
On Tue, Aug 9, 2022 at 1:50 AM Bryan Mumford wrote:
> I’m working from Albert Waugh’s book “Sun dials, Their Theory and
> Construction”.
Is this real or a concept? The shadows don’t move in the rest of the image.
- Bill
On Sun, Oct 30, 2022 at 7:14 AM Alexei Pace wrote:
> Interesting one in Rue Montmartre
> https://www.instagram.com/reel/Cj0hS2JIPQV/?igshid=YmMyMTA2M2Y=
>
> On Wed, Oct 26, 2022, 11:58 Werner Riegler wrote:
>
>>
Hello Valentin,
My version of DeltaCad (10.0.0 for Mac) will not run .bas macros, only
.scpt macros.
Do you know if there is a way to get your macros to run on this version of
deltacad?
-Best, Bill
On Mon, Oct 31, 2022 at 4:32 AM Valentin Hristov
wrote:
> Greetings from Bulgaria to the sundial
I seem to recall Fred contributing to a similar conversation a few years
ago. Speaking from ignorance, I think the sun will not be at exactly 0
declination at 180 longitude because the moon can pull the earth above or
below the ecliptic depending on the lunar orbit. I think the effect is
tiny, and
or a different simple-to-use 2-D CAD
program to recommend? I really like DeltaCad but I don't see how to get
around this.
Best,
Bill Gottesman
---
https://lists.uni-koeln.de/mailman/listinfo/sundial
My guess on this one (without using mirrors):
Point the bottom of an empty can at the sun. The shadow inside the can
now points in the direction of the sun, though the definition of "in the
direction of the sun" in this case is debatable.
-Bill
On Mon, Mar 11, 2024 at 9:33 AM Chris Lusby Taylor
Great, thanks Fred.
-Bill
On Tue, Aug 27, 2024 at 11:04 PM Fred Sawyer wrote:
>
> Paul Nibley at the 2003 conference in Banff.
>
---
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