New Dutch sundial book is out

[Maes, F.W.]

Dear sundial friends,

As many of you may know, I have written and have been teaching an
introductory sundial course for members of the Netherlands' and Flemish
Sundial Societies. Now I have reworked the course material into a book
aimed at a general, Dutch speaking readership. It is the first such book in
70 years; the predecessor dates from 1953!

Although the book is in Dutch, the multitude of nice photos and diagrams
illustrating the sundial concepts and the many sundial types covered in the
thirteen chapters may be enjoyable in itself.

The book is being published by The Netherlands' Sundial Society. Because of
the limited print run, the book is only available through our website,
*www.zonnewijzerkring.nl
*, where also the contents listing and an
example of a double page can be found.

Best regards,
Frans


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Hans de Rijk (Bruno Ernst) passed away

[Maes, F.W.]

Dear all,

We deeply regret to inform you that Hans de Rijk, founding member in 1978
and honorary member of the Netherlands' Sundial Society, passed away on
November 23, at the age of 95. He served in the Board of the Society for
many years and wrote some 150 articles in its Bulletin. Among these were
important contributions, such as a latitude independent sundial, and the
family of equator projection dials. A more playful result of his creativity
were 'postcard dials', which he used to design while waiting for his
Chinese take-away dinner.

Hans was a popularizer of mathematics and astronomy and wrote many books
about these subjects, under the pseudonym Bruno Ernst. His motto was:
"Nescius omnium curiosus sum", I don't know anything but I am anxious to
know everything. His eagerness to learn was equalled by his striving and
ability to teach. He has been a teacher of mathematics and physics, founded
the mathematics magazine 'Pythagoras' and the physics magazine
'Archimedes', aimed at secondary school students. He founded the first
public astronomical observatory in the Netherlands. He also founded the
organization 'Ars et mathesis', where art and mathematics meet, and its
magazine with the same name. He became friends with the famous Dutch artist
Maurits Cornelis Escher and wrote several books about Escher's work. Later
on, he wrote extensively about impossible figures.

Planetoid 11245 bears his name.

We lose a generous, inspiring, modest and productive diallist and friend.

If you would like to contact his family directly, the address for
correspondence is:
Stationsstraat 114
3511 EJ Utrecht
The Netherlands

On behalf of the Netherlands' Sundial Society,
Frans Maes
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Hans de Rijk (Bruno Ernst) passed away

[Maes, F.W.]

Dear all,

We deeply regret to inform you that Hans de Rijk, founding member in 1978
and honorary member of the Netherlands' Sundial Society, passed away on
November 23, at the age of 95. He served in the Board of the Society for
many years and wrote some 150 articles in its Bulletin. Among these were
important contributions, such as a latitude independent sundial, and the
family of equator projection dials. A more playful result of his creativity
were 'postcard dials', which he used to design while waiting for his
Chinese take-away dinner.

Hans was a popularizer of mathematics and astronomy and wrote many books
about these subjects, under the pseudonym Bruno Ernst. His motto was:
"Nescius omnium curiosus sum", I don't know anything but I am anxious to
know everything. His eagerness to learn was equalled by his striving and
ability to teach. He has been a teacher of mathematics and physics, founded
the mathematics magazine 'Pythagoras' and the physics magazine
'Archimedes', aimed at secondary school students. He founded the first
public astronomical observatory in the Netherlands. He also founded the
organization 'Ars et mathesis', where art and mathematics meet, and its
magazine with the same name. He became friends with the famous Dutch artist
Maurits Cornelis Escher and wrote several books about Escher's work. Later
on, he wrote extensively about impossible figures.

Planetoid 11245 bears his name.

We lose a generous, inspiring, modest and productive diallist and friend.

If you would like to contact his family directly, the address for
correspondence is:
Stationsstraat 114
3511 EJ Utrecht
The Netherlands

On behalf of the Netherlands' Sundial Society,
Frans Maes
---
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Re: Is this an educational sundial, or a 'NON-dial'?

[Maes, F.W.]

Hi all,

One property of the analemmatic dial I like to stress: when it has the
right size, you can act as gnomon yourself. This makes it an interactive
instrument, which is appealing: you have to DO something to get the time.
And with the good frame of mind it makes you feel part of the celestial
gearworks, which may even be more satisfying.

Best regards,
Frans Maes



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On Sat, Apr 3, 2021 at 10:28 PM Jack Aubert  wrote:

> The author’s web site seems to be an attempt to monetize has plans for
> analemmatic dials claiming that the whole thing is educational.  There is
> even a link for franchised distributors!  I suppose it would be interesting
> to see what kind of information is contained in the book.  The drawing on
> the cover is, like a stopped watch, occasionally correct – but only once a
> day and only if you decide what part of the shadow to use.  It looks like a
> scam.
>
>
>
> My personal view of analemmatic dials is that they can be decorative and
> even entertaining, but are not very educational at all.  It is hard enough
> for me visualize the projection of a conic section onto a horizontal plane
> and relate it to the sky and the sun let alone explain it to a kid.  It’s
> somewhere between magic and a trick pool shot.
>
>
>
> Jack Aubert
>
>
>
>
>
> *From:* sundial  *On Behalf Of *R. Hooijenga
> *Sent:* Saturday, April 3, 2021 3:47 PM
> *To:* sundial@uni-koeln.de
> *Subject:* RE: Is this an educational sundial, or a 'NON-dial'?
>
>
>
> For this kind of instrument, I personally like to use the term 'Undial'.
>
> So far, it didn't catch on, however - pity! 
>
>
>
> Good Easter,
>
> Rudolf Hooijenga 52 30 N 4 40 E
>
>
>
> -Oorspronkelijk bericht-
>
> Van: sundial  Namens Linda Reid
>
> Verzonden: zaterdag 3 april 2021 20:04
>
> Aan: sundial@uni-koeln.de
>
> Onderwerp: Is this an educational sundial, or a 'NON-dial'?
>
>
>
>
>
> [...]  but looking at the illustration on the front cover, it seems to be
> a 'NON-dial'!
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Greco-Roman sundials

[Maes, F.W.]

Dear Karlheinz,
Thank you for this impressive gift to Mankind!
Best regards,
Frans Maes


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On Tue, Feb 2, 2021 at 7:30 PM Karlheinz Schaldach <
karlheinz_schald...@t-online.de> wrote:

> Hello,
>
> please take note that my new books on Greco-Roman sundials entitled
>
>
> *Die antiken Sonnenuhren Griechenlands: Die Funde in historischer Sicht 
> (**Berlin
> Studies of the Ancient World 76/1)**, *edition topoi, Berlin 2021 (ISBN
> 978-3-9820670-5-6).
>
>
>
> *Die antiken Sonnenuhren Griechenlands: Kataloge – Analysen – Texte (**Berlin
> Studies of the Ancient World 76/2)**, *edition topoi, Berlin 2021 (ISBN
> 978-3-9820670-7-0)
>
>
>
> are published.
>
>
>
> Though they are in German some of you may able to read. You can download
> the pdf-files for free:
>
>
>
> https://refubium.fu-berlin.de/handle/fub188/29027
>
>
> https://refubium.fu-berlin.de/handle/fub188/29030.
>
>
>
> Best wishes,
>
>
>
> Karlheinz Schaldach
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Fer's legacy - diptych

[Maes, F.W.]

Dear Alistair,

I am glad you appreciate the effort we invested in saving the English
version of Fer's legacy. Transmitting the original 360 Dutch articles from
Fer's html-version into the CMS of our present website was quite a job.
Repeating that for the 360 English articles (skillfully translated by our
secretary Ruud Hooijenga) was beyond our stamina. The present solution,
keeping the English html-files and linking to the database for the figures,
appears to be a workable compromise.

It might be interesting for the list members that the English summaries of
the articles in our Bulletin from 1998 onward and its successor Zon & Tijd,
are also available from the English section of our website,
www.zonnewijzerkring.nl, via the link Journal Contents.

As far as I know, Fer has not dealt with the construction of Bab. & Ital.
hour lines in a concave saucer.

Best regards,
Frans Maes

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On Mon, Sep 7, 2020 at 3:44 PM Alastair & Sheila  wrote:

> Hello Frans
>
>
>
> Your link to all the articles of Fer’s Legacy is wonderful. Thank you very
> much for telling us about it. I had already seen a copy of his article
> "Construction of hemispherium", showing how to generate Babylonian and
> Italian hour lines in a hemisphere bowl. Do you know if he described a
> method for doing the same lines in a spherical concave saucer, not a bowl,
> like the diptych dials by Reinman of Nuremberg and others? There must have
> been a method that worked, or was it custom and practice perhaps.
>
>
>
> Good wishes
>
>
>
> Alastair Hunter
>
> __
>
> Macmillan Hunter Sundials, 3 Peel Terrace, Edinburgh EH9 2AY, Scotland, UK
> Telephone: 44 0 131 468 2616  Email: sundi...@macmillanhunter.co.uk
>
> Website: https://www.macmillanhunter.co.uk/
> __
>
>
>
> *From:* sundial  *On Behalf Of *Maes, F.W.
> *Sent:* 03 September 2020 13:49
> *To:* siegfried.netzb...@t-online.de
> *Cc:* sundial@uni-koeln.de
> *Subject:* Re: Fake "trifilar" Sun Dial?
>
>
>
> Dear Siegfried,
>
>
>
> Bernard Rouxel of France designed this original sundial.
> It got him second prize in the Italian "Le ombre del Tempo” contest of
> 2008.
>
>
>
> It was discussed by the late Fer de Vries in one of his online articles.
>
> That website does not exist anymore, but you can find his articles in
> "Fer's legacy":
>
> - Go to www.zonnewijzerkring.nl
>
> - Click the English flag
>
> - Click "Downloads"
>
> - At the bottom of the page, download the zip-file and unzip
>
> - Open "FersLegacy.html"
>
> The article is in the section "Article of the Month", November 2009.
>
> Enjoy!
>
>
>
> Best regards,
>
> Frans Maes
>
>
>
>
>
>
>
> On Thu, Sep 3, 2020 at 10:34 AM Siegfried Netzband <
> siegfried.netzb...@t-online.de> wrote:
>
> Dear sundialists,
>
> found the attached picture in an old archive and do not have any details
> about it.
>
> The dial shown seems to be somethig like a "bifilar sundial with three
> straight wires". The wires obviously do not touch one another. The picture
> was taken at the moment when all wire shadows cross in one point on the
> dial face suggesting that the sundial  shows the time at that moment (and
> any other?). There is no dial face visible. What kind of sun dial is that -
> what could be the idea behind it and it´s purpose?
>
> Is there anyboddy out threre who could answer the following questions and
> can help me to solve my problem, i.e. clarify that sun dial:
>
> - Has any one seen that picture before? If so, do you have any details
> about it? Please let me know.
>
> - The originator of that sun dial must have had some very special ideas
> when constructing that sun dial. To the best of my knowledge a picture like
> that where the shadows of three wires which do not touch one another,
> mounted at different heights and angles across the face of the dial, cross
> in one point on the face of the dial, can only be taken at at most 2 times
> a year, each time at exactly the same solar time. Am I right or does there
> realy exist something like a "trifilar sundial" as shown in the picture
> idicating time over the year?
>
> - Taking the sun dial shown to a singular, simplistic extreme: At whatever
> a

Re: Fake "trifilar" Sun Dial?

[Maes, F.W.]

Dear Siegfried,

Bernard Rouxel of France designed this original sundial.
It got him second prize in the Italian "Le ombre del Tempo” contest of
2008.

It was discussed by the late Fer de Vries in one of his online articles.
That website does not exist anymore, but you can find his articles in
"Fer's legacy":
- Go to www.zonnewijzerkring.nl
- Click the English flag
- Click "Downloads"
- At the bottom of the page, download the zip-file and unzip
- Open "FersLegacy.html"
The article is in the section "Article of the Month", November 2009.
Enjoy!

Best regards,
Frans Maes



On Thu, Sep 3, 2020 at 10:34 AM Siegfried Netzband <
siegfried.netzb...@t-online.de> wrote:

> Dear sundialists,
>
> found the attached picture in an old archive and do not have any details
> about it.
>
> The dial shown seems to be somethig like a "bifilar sundial with three
> straight wires". The wires obviously do not touch one another. The picture
> was taken at the moment when all wire shadows cross in one point on the
> dial face suggesting that the sundial  shows the time at that moment (and
> any other?). There is no dial face visible. What kind of sun dial is that
> - what could be the idea behind it and it´s purpose?
>
> Is there anyboddy out threre who could answer the following questions and
> can help me to solve my problem, i.e. clarify that sun dial:
>
> - Has any one seen that picture before? If so, do you have any details
> about it? Please let me know.
>
> - The originator of that sun dial must have had some very special ideas
> when constructing that sun dial. To the best of my knowledge a picture like
> that where the shadows of three wires which do not touch one another,
> mounted at different heights and angles across the face of the dial, cross
> in one point on the face of the dial, can only be taken at at most 2 times
> a year, each time at exactly the same solar time. Am I right or does there
> realy exist something like a "trifilar sundial" as shown in the picture
> idicating time over the year?
>
> - Taking the sun dial shown to a singular, simplistic extreme: At whatever
> angles or hights multiple wires might run across a dial and touch each
> other at their crrossing point, the dial would simply work and could be
> calculated taking the crossing / touching point as the tip of the gnomon,
> the node of the dial. Correct?
>
> - Does any one know wether H. Michnik, the inventor of the bifilar sun
> dial and its theory in 1923,  has made any mathematical statement about
> "multifilar sundails"?
>
> Thank you for your help and
>
> Kind Regards
>
> Siegfried
>
>
>
>
>
> Siegfried Netzband
>
> Hebelstr. 12
>
> 75233 Tiefenbronn
>
> Tel: 07234 2802
>
> Fax: 07234 942909
>
> Mob: 0151 53083636 / 0160 1531634
>
> E-Post: siegfried.netzb...@epost.de
>
> Skype: siegfried75233
>
> www.ferienhaus-frieseneck.de
>
>
>
>
>
>
>
>
>
>
> 
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
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Re: Denizli sundial

[Maes, F.W.]

A report on:
https://indiablooms.com/travel-details/N/1164/2-000-year-old-sundial-recovered-in-turkey-s-anatolia.html
says the following:
"Inscribed on the dial are the Greek word ‘Ksimerini’, or winter on the
upper part; ‘Isimerini’, or solstice, which denotes the equality of day and
night in the middle; and ‘Terini’, or summer in the bottom."

Ksimerini would in Greek start with Ξ (ksi), but a close look at the
initial, hi-res photo strongly suggests that the first character is X
(chi), in accordance with what John Davis and John Wilson's wife read.

So it seems the names are spelled as follows:
XIMEPINH = winter solstice
IΣHMEPINH = equinox
TEPINH = summer solstice
in which X is Greek chi, P is Greek rho, H is Greek eta.

A photo further down the article shows clearly that the front is cut away.

Best regards,
Frans Maes


On Thu, Apr 9, 2020 at 9:54 AM John Davis 
wrote:

> Dear Frans,
>
> The picture that Dan-George pointed us to is excellent and intriguing too.
> My reading of the lettering is slightly different from yours. Starting from
> the top (presumably the winter solstice), I get
>
> X  I  M  E  P  I  N  H
>H  M  E  P  I  N  H
>E  P   IN H
>
> where the columns represent the spaces between the hour lines. There could
> be some misreadings here. It is clearly not the standard Greek system of
> using the first letters of their alphabet as numbers but I don’t recognise
> the names of the seasons either. Looking through Sharon Gibbs’ book, I
> couldn’t find a similar set of inscriptions. Can any classical scholars
> help us?
>
> As a second point, the front face of the marble looks to be vertical in
> the photo but I found another view online which seems to show it cut back
> at an oblique angle. Both forms of dial are known - which is this?
>
> Regards,
>
> John
> —
> Dr J Davis
> Flowton Dials http://www.flowton-dials.co.uk/
> BSS Editor http://sundialsoc.org.uk/publications/the-bss-bulletin/
>
>
> On 8 Apr 2020, at 18:37, Maes, F.W.  wrote:
>
> Dan-George, thank you for the link! That is a beautiful ancient scaphe
> dial.
> The article says: "The sundial features ... Greek names of seasons". I can
> read a number of characters, which at all three date lines (equinox and
> solstices) seem to include MEPINH. What season names are these?
>
> Keep healthy!
> Frans Maes
>
> On Tue, Apr 7, 2020 at 12:33 PM Roser Raluy  wrote:
>
>> Thank you, it looks great!
>> Roser Raluy
>>
>> Missatge de Dan-George Uza  del dia dt., 7
>> d’abr. 2020 a les 10:12:
>>
>>> Hello, I've just read about the discovery of an antique sundial in
>>> Turkey.
>>>
>>>
>>> https://www.dailysabah.com/life/history/2000-year-old-sundial-unearthed-in-southern-turkeys-denizli
>>>
>>> Best regards,
>>>
>>> --
>>> Dan-George Uza
>>> ---
>>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>>
>>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Denizli sundial

[Maes, F.W.]

Dan-George, thank you for the link! That is a beautiful ancient scaphe dial.
The article says: "The sundial features ... Greek names of seasons". I can
read a number of characters, which at all three date lines (equinox and
solstices) seem to include MEPINH. What season names are these?

Keep healthy!
Frans Maes

On Tue, Apr 7, 2020 at 12:33 PM Roser Raluy  wrote:

> Thank you, it looks great!
> Roser Raluy
>
> Missatge de Dan-George Uza  del dia dt., 7
> d’abr. 2020 a les 10:12:
>
>> Hello, I've just read about the discovery of an antique sundial in Turkey.
>>
>>
>> https://www.dailysabah.com/life/history/2000-year-old-sundial-unearthed-in-southern-turkeys-denizli
>>
>> Best regards,
>>
>> --
>> Dan-George Uza
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Can anyone help me to contact Paul Ratto ?

[Maes, F.W.]

Dear Isabella,

The sundial is laid out according to the "Sunclock" design (
www.sunclocks.com), developed by Douglas Hunt from Great Britain. Paul
Ratto is the "order-taker" for North America; see:
www.sunclocks.com/pics/fs-002.htm, about halfway down the page. There is a
link to his own website: www.sunclocks.com/net/ (and his tel.nr.)
Note that the design has been patented, as far as I know.

A healthy and happy New Year to you too!

Best regards,
Frans Maes
The Netherlands


On Tue, Dec 31, 2019 at 1:22 PM Isabella McFedries <
isabella.mcfedr...@gmail.com> wrote:

>
> Could anyone on this 'Mailing List' help me with finding Paul Ratto ?
>
> My daughter would like to create a twin-ring Analemmatic sundial, for
> her Girl Scout Gold Award - as shown on the NASS website page, at the
> URL of:  www.sundials.org/index.php/sundial-registry/onedial/819.html
>
> It seems the "North American Sundial Society" do not have any contact
> details for Paul, but he is mentioned as being the 'designer' of that
> particular layout - and we understand from NASS they are popular with
> Scouts (both boys plus girls), to achieve Community-related awards.
>
>
> If anyone in North America can be of help, I will look forward to any
> information which may assist my daughter to contact Paul Ratto - for
> example a telephone number (if possible), or even a website address.
>
> With my grateful thanks in advance, for whatever details you can give
> me - plus I take this opportunity to wish everyone a Happy New Year.
>
>
> Sincerely,
>
> Isabella McFedries.
>
>
> --
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Wheatstone's polarizing sundial

[Maes, F.W.]

Hi Bill,

You must be right. Earlier, I did not dare to suppose that Wheatstone, a
famous scientist, and William Darker, a valued instrument maker, could err
so clearly, but it's the only explanation left.

Maybe a confusion arose from the report of Wheatstone's presentation in the
Association Meeting in Swansea, August 1848. The report goes (thanks for
the link, Patrick Vyvyan):
"On a plate of glass twenty-five films of selenite of equal thickness are
arranged at equal distances radially in a semicircle [...] and figures
corresponding to the hours are painted above each film in regular order.
[...] the hour is indicated by the figure placed opposite the radius which
contains the most red; the half-hour is indicated by the equality of two
adjacent tints."

The "25 films of selenite" would clearly have enabled to identify full and
half hours by the film that "contains the most red", and quarter hours by
"two adjacent tints". However, the description suggests to paint 25 HOUR
numbers in the semicircle, as we see done today.

The description in the RMG database says that "an instrument of this type
was exhibited at the 1848 meeting". I doubt whether that is true; at least
it cannot be read from the report. Most of the text is devoted to another
polarizing sundial type, of which also no mention of an exhibition is made.
The present type is only described in the last paragraph of the report as
one of "several other forms of the polar clock".

Thanks to all who responded!
Best regards,
Frans Maes

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On Wed, May 22, 2019 at 4:04 PM John Davis 
wrote:

> Hi Frans et al,
>
> Polarizing sundials have featured a number of times in the *BSS Bulletin*.
> In the same issue (21(i), March 2009) as the article by the sadly-missed
> Allan Mills that Mike Isaacs pointed to earlier, Allan had a second
> article, pp. 14-16, on "An Electronic Polarization Sundial and Photometer"
> which shows background experiments on the physics that Wheatstone's device
> is based on. The first of these articles was one of the earliest we printed
> in colour, essential to see the proper effect of Allan's dial.
>
> Earlier articles in the *Bulletin* are by Allan Mills again ("The
> Sellotape Sundial" 98(1) 3-9) and by David Colchester "A polarized light
> sundial" 96(3) 13-15.
>
> I think reading these articles will fully explain Wheatstone's device, of
> which several were evidently made.
>
> Regards,
>
> John
> --
>
> Dr J Davis
> Flowton Dials http://www.flowton-dials.co.uk/
> BSS Editor http://sundialsoc.org.uk/publications/the-bss-bulletin/
> <http://www.sundialsoc.org.uk/bulletin.php>
>
>
>
> On Tuesday, 21 May 2019, 21:06:52 BST, Maes, F.W. 
> wrote:
>
>
> Recently the Tesseract Catalogue 109 was announced on this list. Item nr.
> 13 is a polarizing sundial by Charles Wheatstone. A virtually identical
> dial is in the collection of the Greenwich museums, see:
> https://collections.rmg.co.uk/collections/objects/265579.html.
> I have never understood how this sundial works. The hour scale shows 2 x
> 12 hour numbers in a semicircle. So whatever pattern is observed in the
> black glass reflector, it is obviously supposed to rotate over 180° in 24
> hours, which is half the angular velocity of the sun itself. How does this
> frequency division-by-two come out? Can anybody explain?
>
> Thanks!
> Frans Maes
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Wheatstone's polarizing sundial

[Maes, F.W.]

Recently the Tesseract Catalogue 109 was announced on this list. Item nr.
13 is a polarizing sundial by Charles Wheatstone. A virtually identical
dial is in the collection of the Greenwich museums, see:
https://collections.rmg.co.uk/collections/objects/265579.html.
I have never understood how this sundial works. The hour scale shows 2 x 12
hour numbers in a semicircle. So whatever pattern is observed in the black
glass reflector, it is obviously supposed to rotate over 180° in 24 hours,
which is half the angular velocity of the sun itself. How does this
frequency division-by-two come out? Can anybody explain?

Thanks!
Frans Maes
---
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Re: dischrony

[Maes, F.W.]

Dear Fabio,

In The Netherlands we use "lengtecorrectie", abbreviated LC, which would
translate to "longitude correction" in English.
Some (international) standardization of terminology would be nice!

Best regards,
Frans Maes

On Tue, Mar 12, 2019 at 2:06 PM Michael Ossipoff 
wrote:

> I usually say "Longitude-Correction".  Of course, for sundials, it's
> always expressed in minutes.
>
> But I like "Local Constant", because it's shorter.
>
> What's wrong with "Local Constant"?   It *is* a constant, for a given
> locale.
>
> I'll probably start saying "Local Constant".
>
> Usually I don't know what the EqT is, but I know the local constant here,
> and so, for a good estimate, from Standard-Time, of Sundial-Time (Local
> True Solar Time), I just apply the local constant, adjusted for the mean of
> the annual EqT extremes, to get the least-maximum-error guess for
> Sundial-Time.
>
> Michael Ossipoff
>
> 2019, Week 12, Tuesday  (South-Solstice WeekDate Calendar)
>
>
>
> On Tue, Mar 12, 2019 at 6:55 AM fabio.sav...@nonvedolora.it <
> fabio.sav...@nonvedolora.it> wrote:
>
>> hi all, I've a matter to put to you.
>>
>> In Italy some sundials show the written 'costante locale', that can be
>> translated as 'local constant'.
>> The authors of these sundials use this expression meaning the time
>> difference between the Local Sun Time and the Time-Zone Sun Time.
>> This 'local costant' is an angle if it highlights the difference of
>> longitude or a time if it highlights the difference between the two Sun
>> Time.
>>
>> I don't really like this expression. I think that the term 'costant' is
>> misleading: the shown value depends on the selected meridian, it could
>> not be that of the Time-Zone (e.g, outside UK, the one of the national
>> observatory used in the past).
>> Moreover the term suggests that there is a not better identified costant
>> in that location but it isn't a costant, it is a choice on how to show
>> the time.
>>
>> I started to look for a more proper expression.
>> I'd like to know if there are any terms used in other languages, may be
>> that a proper expression already exists.
>> Anyway I found two italian terms that I think to propose as an
>> alternative to the italian diallists, these terms may be used also in
>> english so I'd like to know your thoughts.
>> The first term is 'dislocation' (dislocazione), it means a different
>> location and it refers to an angle.
>> The second one is 'dischrony' (discronia) and it means a different time.
>> This terms is curious because it rarely appears on the italian
>> dictionaries, it is a technical term used in the medical field to
>> indicate the cause of the 'jet lag' (while dysrhythmia is used for the
>> effects), that is: to live with a different time.
>>
>> ciao Fabio
>>
>>
>> --
>> Fabio Savian
>> fabio.sav...@nonvedolora.it
>> www.nonvedolora.eu
>> Paderno Dugnano, Milano, Italy
>> 45° 34' 9'' N, 9° 9' 54'' E, UTC +1 (DST +2)
>>
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
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Dutch sundial journal renewed

[Maes, F.W.]

Dear sundial friends,



This is to let you know that the Sundial Society of Flanders (Belgium) has
discontinued the publication of "Zonnetijdingen", as it appeared
increasingly difficult to gather enough articles.

The Belgian Society contacted the Netherlands' Sundial Society (De
Zonnewijzerkring), which has been publishing its "Bulletin" for 40 years
already.
The two societies decided to join editorial forces in a new journal, *ZON &
TIJD* (Sun & Time).

The fact that Dutch is the common language of both societies made this an
easy choice.

Our Austrian friends may note some similarity with the title of their
journal, “Sonne + Zeit”. We hope they take this as a compliment J

You may have a look at the first issue, which has articles by Dutch and
Flemish authors. The issue is temporarily available from the English
section of the new website of De Zonnewijzerkring, at:

*www.dezonnewijzerkring.nl/pages/en/downloads.php
. *The journal is
in Dutch, of course, but features an English summary of the contents in the
back on p. 37-38.



Best regards,
Frans Maes (NL) & Eric Daled (BE), editors
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Re: star-shaped sundial in Finland

[Maes, F.W.]

Dear Fabio,

There are several similar sundials in the Netherlands. One example can be
seen at:
http://www.fransmaes.nl/zonnewijzers/en/menkema-e.htm
Typically, they are combined with two cubic sundials, rotated 45° with
respect to another.
The points of the star all form small polar dials, each covering only a
couple of hours. The bottom equatorial dial has hours from 6-6 (18) hr. In
my country, the top equatorial dial has hours from 4 to 8 (20). The one in
Finland from 3 to 9 (21), which fits a more northern location. Not as far
north as Tornio, however, which is almost at 66° North, quite close to the
arctic circle.

Best regards,
Frans Maes




Virusvrij.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Thu, Mar 22, 2018 at 12:44 PM, fabio.sav...@nonvedolora.it <
fabio.sav...@nonvedolora.it> wrote:

> Hi all
>
> I've a contact with Susanna Kuokkanen, a student of archeology of the
> University of Oulu, Finland.
> Oulu is quite close to the polar circle, on the gulf of Botnia.
>
> A star-shaped sundial was found during an axcavation for the construction
> of a building in Tornio.
> Tornio is just at the top of the gulf, on the border with Sweden.
> Susanna sent me the photos of the sundial, you can see the card FI8 in
> Sundial Atlas (www.sundialatlas.eu/atlas.php?so=FI8).
>
> It is an equinoctial sundial, star-shaped with 12 points, and another
> sundial on its upper surface, without the gnomon.
> Susanna was instructed by the university to do a research, later the
> sundial will be moved to the Tornio museum.
> She hasn't gnomonic notions and she found in Sundial Atlas some
> star-shaped sundials and, above all, the menu 'gnomolab' where there are
> many models of paper sundials. One of these, the app 7, is a star-shaped
> sundial strikling similar with the find of Tornio.
> I helped her to build the paper sundial for her latitude and it shows the
> same indications.
> In the area of Tornio there were many merchants from XVI to XVIII
> centuries, it was a rich area for the fur market, and she thinks the
> sundial come from another southern area, carried by one of these merchants.
>
> I asked her news about the basement, it'd have clarified the latitudine of
> its origin, but it wasn't found.
>
> I'm writing a report for her with explanations how a star-shaped works but
> an important point of her research is to understand the origin of the
> sundial.
> Have you some ideas about the probable provenance ?
>
> thank you, Fabio
>
> --
>
> Fabio Savian
> fabio.sav...@nonvedolora.it
> www.nonvedolora.eu
> Paderno Dugnano, Milano, Italy
> 45° 34' 9'' N, 9° 9' 54'' E, UTC +1 (DST +2)
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Hemicyclium correction

[Maes, F.W.]

Hi Patrick,

Thanks for pointing this out. Fortunately, I am still alive and sometimes
kicking a bit ...

I put the link to Fer de Vries' article temporarily on my own website as it
was the quickest and easiest way to answer a query by someone on this list.
By now, the (same) article is also available on the website of the Dutch
Sundial Society.

Best regards,
Frans Maes


Virusvrij.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sun, Oct 22, 2017 at 7:36 PM, Patrick Powers <
patrick_pow...@compuserve.com> wrote:

> Hi Brad,
>
> My message re your interest in hemicyclia should have made it clear that
> it was Fer De Vries’s original work on the construction of a Hemispherium
> that he placed on his website and which was republished after his death by
> Frans Maes and then placed on his own website for us to read today. My
> sincere apologies to Frans!
>
> Patrick
>
> *From:* Patrick Powers 
> *Sent:* Sunday, October 22, 2017 12:40 PM
> *To:* Brad Thayer  ; sundial@uni-koeln.de
> *Subject:* Re: Hemicyclium correction
>
> Hi Brad
>
> Further to your interest in an hemicyclium you might like to know of this
> link to the former webpages of the late Frans Maes who set out his
> instructions for *“Construction of Hemispherium”* some time ago and which
> is based on several earlier documents – all referenced.  You might find it
> useful – or at least interesting!
>
> http://www.fransmaes.nl/zonnewijzers/downloads/hemisph.htm
>
> Good luck
>
> Patrick
>
>
>
> *From:* Brad Thayer 
> *Sent:* Monday, October 16, 2017 1:48 PM
> *To:* sundial@uni-koeln.de
> *Subject:* Hemicyclium correction
>
>
> I am looking to make a hemicyclium-type sundial (half-hemisphere) in a
> metal working class.  What little I can find on them says they are
> inaccurate, without being very clear on the problem.  It appears to me the
> only issue is it needs to be tilted so that the gnomon aligns with the
> Earth’s rotation axis; thus the half-bowl faces south and the gnomon points
> south, but the end of the gnomon that attaches to the bowl points north.
> Am I missing anything?  I am also looking to use an analemma-shaped gnomon
> to cast the shadow on the bowl, and at least month lines for the solar
> elevation.  The bowl will also have a rod and bracket on the bottom to
> allow it to be rotated for daylight-savings time and for local longitude
> corrections.
>
>
>
> Thanks in advance -- Brad
>
> --
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
>
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Re: Are there some Sundial Designers, in INDIA ?

[Maes, F.W.]

Hi Frank,

Although it was not the start topic, I had a look at the new (no capital N)
Delhi sundial. According to the newspaper article, "the sundial has been
recently certified as one of the largest scientifically ACCURATE sundials
in the world." (my capitalization). Even if the attachment would not pass
the size filter, it is clear that the hour lines, visible from outer space,
do not warrant this attribution.

Best regards,
Frans Maes

On Mon, Dec 19, 2016 at 8:08 AM, Beverly Stimpson <
beverly.stimp...@gmail.com> wrote:

> In message <2a50dfe...@users.interwebs.com>
>   Beverly Stimpson  wrote:
>
> >
> > Do the members of this list know, whether there are some (or even ANY)
> > sundial designers in INDIA - since I have a potentially very lucrative
> > business proposal, especially for use within the 'Educational Sector'.
> >
>
>
> Thanks to the (few) people, who had contacted me privately - especially
> Martina Addiscott, who gave me the perfect 'contact' for my purposes.
>
> Though it may seem strange, their main thrust is "aero-modelling" (see
> website at www.aero-sports.in) - but those people have the exact mix of
> educational contacts and expertise, needed for my business proposal.
>
>
> One of their 'Franchisees' is Rajbir Singh Grewal 
> who operates a travelling "StarLab" planetarium, which visits schools
> across India - and he has already expressed interest in my idea, which
> involves combining 'sundials' with 'physical education'.  Please note,
> it has NOTHING to do with playground sundials of the Analemmatic type.
>
> Incidentally, in answer to a previous question - I would NOT require
> 'manufacturing' contacts, since if this is needed at all it should be
> within the capability of any individual local school/college in India.
>
>
> Before anyone asks, the reason I have chosen India - is because this
> concept is only suitable for very LOW latitudes within the 'tropics',
> to which traditional sundials (and Analemmatics) are not best suited.
>
> Also, because India is largely an 'English-speaking' country - I will
> therefore avoid any difficulties, associated with language barriers.
>
>
> My thanks again to the people who responded, but I now have the basis
> of this business - with a pre-established 'network', covering India !
>
>
> Regards,
>
> Beverly Stimpson.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Sundials near the Equator

[Maes, F.W.]

Hi David,

I hoped to find a picture of this large Hong Kong equatorial dial with kids
climbing into it. But people are too well-behaving apparently.

On Thu, Mar 24, 2016 at 1:37 PM, Richard Langley  wrote:

> There is the huge Quitsato Sundial near Quito. If you Google "Quitsato
> Sundial" and select Images, you'll find some with people in them.
> -- Richard Langley
>
>
> -
> | Richard B. LangleyE-mail: l...@unb.ca
>|
> | Geodetic Research Laboratory  Web: http://gge.unb.ca
>   |
> | Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142
>  |
> | University of New Brunswick   Fax:  +1 506 453-4943
>  |
> | Fredericton, N.B., Canada  E3B 5A3
>   |
> |Fredericton?  Where's that?  See: http://www.fredericton.ca/
>|
>
> -
>
> 
> From: sundial  on behalf of David <
> da...@davidbrownsundials.com>
> Sent: Thursday, March 24, 2016 9:20 AM
> To: sundial
> Subject: Sundials near the Equator
>
> Dear fellow shadow-watchers...
>
> Can anyone direct me to images of large sundials near to the Equator,
> preferably with some element of human involvement?
>
> David Brown
> Somerton, Somerset UK
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>
> ---
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> ---
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>
>
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Re: Sundials in museums

[Maes, F.W.]

Hi Darek,

While in London/Greenwich, you should not miss the Science Museum. They
have a LOT of (mostly: pocket) sundials on display.

Another must-see is the Deutsches Museum in München. There is a sundial
garden on a 5th floor outside terrace, which is a showcase of all possible
- modern - types.

Enjoy!
Frans Maes

On Mon, Jan 11, 2016 at 6:21 AM, Roger Bailey  wrote:

> Hi Darek,
>
> Participating in NASS and BSS conferences over the past 20 some years has
> provided the opportunity to some amazing collections of historical
> scientific instrument. Here are a few that I have had the opportunity to
> visit , two in the USA and two in the UK. All were worth the trip.
>
> Harvard University Collection of Historical Scientific Instruments.
> https://chsi.harvard.edu/index.html
> Contact Dr. Sara Schechner, the David P. Wheatland Curator of the
> Collection of Historical Scientific Instruments
>
> Adler Planetarium, Chicago  http://www.adlerplanetarium.org/ or
> specifically astronomy in culture
> http://www.adlerplanetarium.org/events/astronomy-in-culture-2-2016-01-10/
>
> Cambridge University, Museum of the History of Science.
> http://www.hps.cam.ac.uk/whipple/ An remarkable collection of sundials
> and astronomical instruments
>
> Royal Museums Greenwich, Astronomical and navigational instruments. The
> National Maritime Museum (NMM) holds a large and varied collection of
> astronomical and navigational instruments, 3587 items. These range from
> astrolabes and armillary spheres to quadrants, nocturnals and sundials.
> http://collections.rmg.co.uk/collections.html#!csearch;authority=subject-90227;browseBy=collection
> .
>
> This is my short list. There are many others worth exploring.
> Regards, Roger Bailey
>
> --
> From: "Darek Oczki" 
> Sent: Saturday, January 09, 2016 4:54 AM
> To: 
> Subject: Sundials in museums
>
> Hello
>> I wish everyone on this list plenty of sunshine in the 2016.
>>
>> I've got a question. Is there a list/register of sundial collections in
>> museums arround the world? I would like to ask your advise which ones are
>> worth visiting.
>>
>> During Christmas I was in Milano, Italy and as they were open I visited
>> the Poldi Pezzoli Museum to see what sundials they got. I found out they
>> have a very nice collection consisting of 200 pieces of all kinds of
>> portable sundials including a Navicula and 2 canon dials. I took a lot of
>> photos.
>>
>> What other places would you recommend?
>>
>> --
>> Best regards
>> Darek Oczki
>> 52N 21E
>> Warsaw, Poland
>> GNOMONIKA.pl
>> Sundials in Poland
>> http://gnomonika.pl
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
>>
>> -
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 2016.0.7294 / Virus Database: 4489/11357 - Release Date: 01/08/16
>>
>> ---
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>
>
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Re: Construction of a Hemispherium

[Maes, F.W.]

Dear all,

Thanks to the invaluable resources of archive.org, Fer de Vries' webpage on
the construction of a hemispherium could be reconstructed. For convenience
I uploaded it to: www.fransmaes.nl/zonnewijzers/downloads/hemisph.htm.

Best regards,
Frans Maes

On Mon, Sep 28, 2015 at 9:03 PM, Dan-George Uza <cerculdest...@gmail.com>
wrote:

> Dear Frans,
>
> As far as I can see your message did NOT go to the SML.
>
> Dan
>
> On Wed, Sep 16, 2015 at 12:59 PM, Maes, F.W. <f.w.m...@rug.nl> wrote:
>
>> Dear all,
>>
>> Thanks to the invaluable resources of archive.org, Fer de Vries' webpage
>> on the construction of a hemispherium could be reconstructed. For
>> convenience I uploaded it to:
>> www.fransmaes.nl/zonnewijzers/downloads/hemisph.htm.
>>
>> Best regards,
>> Frans Maes
>>
>> On Tue, Sep 15, 2015 at 2:38 PM, Thibaud Taudin Chabot <tcha...@dds.nl>
>> wrote:
>>
>>> here is the missing picture
>>> Thibaud
>>>
>>> At 21:25 14-9-2015, Dan-George Uza wrote:
>>>
>>> Dear Frans et al.,
>>>
>>> Enclosed is the article Roger Bailey sent me. As other people expressed
>>> interest I wanted to host it on my blog but then I thought: wouldn't it be
>>> more suitable to appear on a Dutch website? Be warned, a couple of links
>>> are still missing.
>>>
>>> Regards,
>>>
>>> Dan Uza
>>>
>>> On Mon, Sep 14, 2015 at 12:11 AM, Maes, F.W. <f.w.m...@rug.nl> wrote:
>>> Hi Dan,
>>>
>>> Fer's message of 1996, still in the archives, said:
>>> "On the Internet I have made a page with drawings how to construct a
>>> hemispherium. [...] This page will be removed after some time"
>>> As you may know, Fer passed away earlier this year. I am afraid that the
>>> page indeed has been lost, unless someone has downloaded and stored it
>>> locally.
>>>
>>> The article in the Bulletin of the Dutch Sundial Society 1979, to which
>>> Fer referred, is available as a scan; in Dutch, 7 pages.
>>>
>>> Best regards,
>>> Frans Maes
>>>
>>> On Sun, Sep 13, 2015 at 7:57 PM, Dan-George Uza <cerculdest...@gmail.com
>>> > wrote:
>>> Hello!
>>>
>>> I am trying to locate a copy of Fer de Vries' website article detailing
>>> the construction of a hemispherium sundial. The link was posted here in
>>> 1996 but it is no longer available. Please help if you can.Â
>>>
>>> ​Dan Uza
>>>
>>>
>>> ---
>>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>>
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Dan-George Uza
>>> http://cerculdestele.blogspot.com
>>> Content-Type: application/zip; name="Hemispherium.zip"
>>> Content-Disposition: attachment; filename="Hemispherium.zip"
>>> X-Attachment-Id: f_iekbbovk0
>>>
>>>
>>
>
>
> --
> Dan-George Uza
> http://cerculdestele.blogspot.com
>
---
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Re: Please help identify this architectural sundial and location.

[Maes, F.W.]

Hi all,

The sundial is located in Munich, in the terminal of the underground
(U-bahn) at Messestadt-Ost (Trade fair). Not quite in the middle of Munich,
though. It is nr. DGC-11098 in the database of the German Chronometrical
Society.
The time is read where the shadow of the upper edge intersects with the
date line. Only three date lines are laid out, and they change shape
considerably, the summer solstice line even twisting into a loop. This
makes it not easy to get an accurate reading throughout the year.
This is an interesting example of a monofilar dial.

Best regards,
Frans Maes

On Thu, Jun 25, 2015 at 7:26 PM, kool...@dickkoolish.com wrote:

 https://www.flickr.com/photos/suzanne-gibson/8377866276


  Please help identify this architectural sundial and location recently
  posted on Flickr.
 
 
 https://www.flickr.com/photos/schraeglage-urbex/19116095082/in/explore-2015-06-24/
 
  Larry Bohlayer
 
 
  ---
  https://lists.uni-koeln.de/mailman/listinfo/sundial
 
 


 ---
 https://lists.uni-koeln.de/mailman/listinfo/sundial


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Re: Clouding the issue

[Maes, F.W.]

Hi all,

Wheatstone designed still another type of polarization dial than the one
described by Jim Mahaffey. A specimen is in the collection of the British
National Maritime Museum in Greenwich, see
http://collections.rmg.co.uk/collections/objects/265579.html.
When viewing the celestial pole, the polarization pattern of the sky is
visible, consisting of two light and two dark regions, which rotate around
the pole together with the sun.
What I don't understand from the NMM dial: why does it have twice the hour
numbers from 1-12 in a semicircle, while the sun rotates through 24 hours
in a full circle?
Allan Mills made a modern version, using sellotape instead of selenite; see
BSS Bulletin 1998 nr. 1. It has one set of 1-12 hour numbers in a
semicircle, as one would expect.

Best regards,
Frans Maes

On Mon, Mar 30, 2015 at 7:06 PM, Ian Maddocks ian_maddo...@hotmail.com
wrote:

  Hi

 So what is required is some coating that absorbs in the radio part of the
 spectrum (i.e. not absorbed by clouds), then reemits in the visible? You
 then coat the dial plate and can tell what is in the radio shadow of the
 gnomon.
 OK, that may be a little outside the box

 Ian
 Chester, UK


 --- Original Message ---

 From: Fred Sawyer fwsaw...@gmail.com
 Sent: 30 March 2015 13:38
 To: Roger Bailey rtbai...@telus.net
 Cc: Sundial Mailing List sundial@uni-koeln.de
 Subject: Re: Clouding the issue

   See Wheatstone's Polarizing Sundial by Jim Mahaffey in The Compendium
 8(2):1-3, Jun 2001.  This is an expanded version of his article that first
 appeared in Optics and Photonic News, 11(7):14-15, Jul 2000.

  Fred


 On Mon, Mar 30, 2015 at 12:24 AM, Roger Bailey rtbai...@telus.net wrote:

  Hello Peter and all,

 Yes, clouds are a significant, perhaps the overwhelming issue with
 sundials. Night knocks out half the time and clouds at least half of the
 remaining daylight hours. Our BSS colleagues know the problem. The most
 common sundial motto is I count only the sunny hours. This is a truly
 defeatist attitude in these days of technology. Can we do better? The
 effects of clouds are subtle. A slight overcast can destroy the contrast
 required to read a sundial. Such sunlight, not enough to cast shadows can
 burn pale skin. Fleeting clouds cause the shadow to bounce back and forth
 giving indeterminate time readings depending on the side of the sun
 obscured. I don't think wavelengths are the solution. Wavelength effects
 giving us red sunsets but there seems to be no advantage through daytime
 clouds. But where there is light, there is hope. Polarization is detectable
 through light clouds. Take that old polarizing filter from your obsolescent
 SLR camera or an old pair of Polaroid sunglasses, hold towards the sun and
 turn to see the polarization of the sky. Direct views of the sun are not
 required. Polarized skylight can tell you where the sun is when it is
 obscured. The polarization effect is evident but not distinct. The
 phenomenon exist and is familiar to photographers with polarizing
 filters, a vanishing species. Has the effect been exploited by gnomonists?
 I don't think so. The opportunity remains, a chimera, like analemmatic
 moondials. I am working on the latter for the NASS conference in Victoria
 BC in June.

 Regards, Roger Bailey

  *From:* Peter Mayer peter.ma...@adelaide.edu.au
 *Sent:* Sunday, March 29, 2015 3:13 PM
 *To:* sundial@uni-koeln.de
 *Subject:* Clouding the issue

  Hi,

 In the Last Word section of a recent _New Scientist_ Stephen Parish
 raised the question of sundials that might work on cloudy days...Clearly,
 polarisation is possible, but I'm doubtful about shadow casting...
 Clouding the issue

- 18 March 2015
- Magazine issue 3013 http://www.newscientist.com/issue/3013. *Subscribe
and save*

 http://subscription.newscientist.com/bundles/bundles.php?promCode=8014packageCodes=PTAofferCode=Qcmpid=nsarticletopintcmp=SUBS-nsarttop
- For similar stories, visit the *Last Word*
http://www.newscientist.com/topic/lastword Topic Guide

 *Are there any wavelengths at which the sun still casts a shadow when the
 sky is full of clouds? Could I make a sundial that would work on a cloudy
 day?*

 *Stephen Parish, London, UK*

 *This article appeared in print under the headline Clouding the issue*
 [image: Issue 3013 of New Scientist magazine]
 http://www.newscientist.com/issue/3013

- From issue 3013 http://www.newscientist.com/issue/3013 of New
Scientist magazine, page 57.

 best wishes,

 Peter

 --
 Peter Mayer
 Department of Politics  International Studies (POLIS)
 School of Social Scienceshttp://www.arts.adelaide.edu.au/polis/
 The University of Adelaide, AUSTRALIA 5005
 Ph : +61 8 8313 5609
 Fax : +61 8 8313 3443
 e-mail: peter.ma...@adelaide.edu.au
 CRICOS Provider Number 00123M
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