subject:"request"

Re: request

2020-08-09 Thread Michael Ossipoff

Determining how much time error, at a certain time, a given
azimuth-alignment-error will cause, or what azimuth-alignment error would
cause a certain time error at a certain time--That isn't an unusual kind of
problem.

But, if you want to use clock-time to set a sundial, then just rotate the
dial till it says the correct Local-True-Solar-Time.

Of course you find the correct Local-True-Solar-Time from the clock-time,
by means of EqT and longitude.

In earlier times, that would often be done by using a noon-line to
determine Local-True-Solar-Noon.

The noon-line drawn north-south to the base of a vertical, which could be a
window-edge or a vertical edge of a square-cross-section pole.

Determining north without a clock or watch can be done by marking the
position of the shadow of some point like the tip of a twig, or a corner at
the top of a square post. Mark the position of the tip-shadow in the
morning, measure from it to the point directly under the shadow-casting
point (which could be determined by a plulmbline).

In the afternoon, when the distance from tip-shadow to the sub-tip point is
the same as before, mark the position of the tip-shadow again. The line
between the marks is east-west, and a line perpendicular to it is
north-south.

That's a way to determine north-south for making a noon-line, by which to
align a sundial at Local-True-Solar-Noon.

Alternatively, one could just wait till it's getting close to noon, and
then start marking the tip-position, and note when it's at its shortest, at
which time it's to the north of the sub-tip point.

Michael Ossipoff

On Sat, Aug 8, 2020 at 12:59 PM André Reekmqns 
wrote:

> Looking for the 3 pages article published in BSS or NASS 10 years? about
> rectifying a misaligned pole-style horizontal or vertical sundial.
>
>
>
> André Reekmans
>
> Sundial Society of Flanders, Belgium.
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
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Re: request

2020-08-09 Thread Steve Lelievre


André,

Maybe one of these?

New Method Of Setting Sundials – An Improvement / Rolf Wieland / The 
Compendium 21(1), March 2014, pp.12-14


Introduction: In The Compendium 20(4) from December 2013 we could read 
on page 4 the following intriguing method of setting a sundial described 
in the Time's Telescope for 1824 (Nov. 1824, p. 283): On a bright day, 
set a watch exactly with the dial at 9 o'clock in the morning, and at 3 
in the afternoon observe the difference between them, and correct the 
dial to half this difference. Proceed in the same manner till the watch 
and dial are found to agree perfectly. This is a surprising and easy 
method and in the beginning I could not believe it would work...



An Easy Method To Find Proper Alignment / Bill Gottesman / The 
Compendium 9(2), June 2002, pp.7-16


Does your sundial read properly all day long, or does its accuracy drift 
during the day? Would you like to have an easy method to determine how 
to adjust your dial’s position to accurately read solar, standard or 
daylight savings time? This article describes a new method for taking 
three time measurements from your dial, and then using that information 
to calculate how to tilt your dial to obtain accurate alignment with the 
North Pole and the time meridian of your choosing



Cheers,
Steve


On 2020-08-08 9:59 a.m., André Reekmqns wrote:


Looking for the 3 pages article published in BSS or NASS 10 years? 
about rectifying a misaligned pole-style horizontal or vertical sundial.


André Reekmans

Sundial Society of Flanders, Belgium.


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Re: request

2020-08-09 Thread Peter Mayer


Dear André,

Could it have been:" Error In A Misplaced Sundial - Fred Sawyer "? 
Compendium (1/4 1994). Let me know if it is and I can forward the pdf.


best wishes,

Peter

On 9/08/2020 2:29:04, André Reekmqns wrote:


Looking for the 3 pages article published in BSS or NASS 10 years? 
about rectifying a misaligned pole-style horizontal or vertical sundial.


André Reekmans

Sundial Society of Flanders, Belgium.


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request

2020-08-08 Thread André Reekmqns

Looking for the 3 pages article published in BSS or NASS 10 years? about
rectifying a misaligned pole-style horizontal or vertical sundial. 

 

André Reekmans

Sundial Society of Flanders, Belgium.

 

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sundial request for Marblehead, Massachusetts

2019-03-01 Thread Schechner, Sara

Dear Fellow Dialists,

Ellaine Rose of Marblehead, Massachusetts would like to have a vertical sundial 
made for her home.  It would be placed on a southwesterly wall facing the 
harbor, where it could be seen from boats.  She envisions a motto, "Time and 
Tide Wait for No One."  She needs help with the layout of hour lines and 
fabrication, but might wish to assist in painting a background scene.

If you are interested in this commission, please contact Ellaine Rose directly 
at ellai...@comcast.net.  I think it will be a 
delightful project to work on.

Best wishes,
Sara

Sara J. Schechner
Altazimuth Arts
42°36'N   71° 22'W
West Newton, MA 02465
http://www.altazimutharts.com/

Sara J. Schechner, Ph.D.
David P. Wheatland Curator of the Collection of Historical Scientific 
Instruments
Lecturer on the History of Science
Department of the History of Science, Harvard University
Science Center 251c, 1 Oxford Street, Cambridge, MA 02138
Tel: 617-496-9542   |   Fax: 617-495-3344
sche...@fas.harvard.edu |@SaraSchechner
http://scholar.harvard.edu/saraschechner
http://chsi.harvard.edu/

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update request from list owner

2015-02-14 Thread Daniel Roth


Dear sundialists!

If not done yet, please update your e-mail address book entry for the 
sundial mailing list address:

Replace sund...@rrz.uni-koeln.de by just sundial@uni-koeln.de
Thank you!

The old address might not work anymore at some point in future.

Best regards and thank you all for your valuable contributions to my 
list for sundialists!

Daniel Roth, sundial mailing list

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Re: Request for information about a type of altitude dial

2014-06-02 Thread John Davis

Hi Steve et al,

It's usually just called a disc dial. I don't think the example shown is 
latitude-adjustable: the suspension point is fixed. All the historical ones 
I've seen are single latitude devices. Only the occulus is adjustable, for date 
(declination). Earlier examples had the hour points set on a concentric circle 
which meant that they were very inaccurate at some times of the year - the 
extension lobe on this one is an empirical attempt to improve things. The 
mathematics are dubious.

The earliest versions seem to be 16th century and there are quite a number from 
the 17th. I have one along similar lines found by a metal detectorist in 
Norfolk (UK).

Regards,

John

 
Dr J Davis
Flowton Dials http://www.flowton-dials.co.uk/

BSS Editor http://www.sundialsoc.org.uk/bulletin.php



 From: Steve Lelievre steve.lelievre.can...@gmail.com
To: sundial@uni-koeln.de sundial@uni-koeln.de 
Sent: Sunday, 1 June 2014, 23:13
Subject: Request for information about a type of altitude dial
 

Hi folks,

http://www.pinterest.com/pin/301178293801331061/

What type of dial is this; I realize it's a form of altitude dial, but is there 
a specific name for it?

The accompanying note states that the dial can be adjusted for latitude by 
moving the attachment point. I don't understand which part of the mechanism 
does that. Can anyone explain it for me?

Lastly, I'm appreciate references for articles or webpages that discuss these 
dials - history and mathematics.

Thanks,
Steve







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RE: Request for information about a type of altitude dial

2014-06-02 Thread Schechner, Sara

There has been some confusion in the discussion so far. Here is my take:

The sundial pictured is called a “vertical disk dial.” It is an altitude
sundial.
The example pictured is similar to one at CHSI (inv. 7270) signed “I W” with a
punch mark of a crown and date 1672. It is for latitude 52° 35'.

Most of the vertical disk dials are for single latitudes, and have a single
suspension point. However, a few try to be adjustable for latitude. At
Harvard, an example is inv. 7264, which is signed and dated “ P. L. K. / 1755.”

I will tweet images of them and post them in this Dropbox:
https://www.dropbox.com/sh/9qg1p0kejm3o842/AACoYez5bVtRU5JhPJuJgOK8a

Sara

Sara J. Schechner
Altazimuth Arts
42°36'N 71° 22'W
West Newton, MA 02465
http://www.altazimutharts.com/

Sara J. Schechner, Ph.D.
David P. Wheatland Curator of the Collection of Historical Scientific
Instruments
Department of the History of Science, Harvard University
Science Center 251c, 1 Oxford Street, Cambridge, MA 02138
Tel: 617-496-9542 | Fax: 617-496-5932 | sche...@fas.harvard.edu
http://scholar.harvard.edu/saraschechner
http://chsi.harvard.edu/

On Sun, Jun 1, 2014 at 6:13 PM, Steve Lelievre
steve.lelievre.can...@gmail.commailto:steve.lelievre.can...@gmail.com wrote:
Hi folks,

http://www.pinterest.com/pin/301178293801331061/https://urldefense.proofpoint.com/v1/url?u=http://www.pinterest.com/pin/301178293801331061/k=AjZjj3dyY74kKL92lieHqQ%3D%3D%0Ar=Y3uaNkd%2BN%2BBEMo7BAxbEQqOqpMk6uxYnCJsB4uxugzo%3D%0Am=izSTWMgNnFv8DfKU%2Bd249F%2B%2FyJSDHvIkXOyVUqkC8%2FU%3D%0As=7631973f481f1363e8d75a48591133eaed99295b1faf9d05a8f4a1ea4c25175d

What type of dial is this; I realize it's a form of altitude dial, but is there
a specific name for it?

The accompanying note states that the dial can be adjusted for latitude by
moving the attachment point. I don't understand which part of the mechanism
does that. Can anyone explain it for me?

Lastly, I'm appreciate references for articles or webpages that discuss these
dials - history and mathematics.

Thanks,
Steve

---
https://lists.uni-koeln.de/mailman/listinfo/sundialhttps://urldefense.proofpoint.com/v1/url?u=https://lists.uni-koeln.de/mailman/listinfo/sundialk=AjZjj3dyY74kKL92lieHqQ%3D%3D%0Ar=Y3uaNkd%2BN%2BBEMo7BAxbEQqOqpMk6uxYnCJsB4uxugzo%3D%0Am=izSTWMgNnFv8DfKU%2Bd249F%2B%2FyJSDHvIkXOyVUqkC8%2FU%3D%0As=dcc654938564a18e96ec2bb9f94d253a409277009b33d3b5467c6486ffb43f43

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