Re: Adjusting dial to new location

[Michael Ossipoff]

I mentioned several alignments, the correction of any one of which could be
used to determine how much the dial-plate should be rotated in its own
plane (either before or after the tip).

Most recently I suggested the altitude of the pointing-direction of the
style.

But it seems to me that it would be easier to correct the
pointing-direction of the noon-line to the hour-angle equal to 180 degrees
+ the westward longitude-offset (the amount by which you want the LTST o a
longitude west of yours…& of course negative if you want it for a longitude
east of yours). In my example, the longitude-offset way7 degrees.

That correction gives a simpler expression for the necessary dial-plate
rotation in its own plane. (…which can be done before or after the tip).

On Tue, Apr 11, 2023 at 08:52 Michael Ossipoff 
wrote:

> I retract the addendum. I wrote it with the notion that the noon-line
> should be under the style.   …as if the dial were intended to read for its
> own longitude.
>
> So, sorry—disregard the addendum (…as you probably already have).
>
> The dial-plate’s rotation in its own plane should be to correct the
> style’s pointing-direction (in altitude or azimuth), as I originally said &
> described.
>
> Correcting its altitude would give an easier equation-solution.
>
>
>
> On Sat, Apr 8, 2023 at 21:25 Michael Ossipoff 
> wrote:
>
>> Addendum:
>>
>> …
>>
>> Instead of finding the dial-plate rotation in its own plane that corrects
>> the style’s pointing-direction, it might be easier to, instead, find the
>> dial-plate rotation in its own plane that puts the dial’s noon-line in the
>> meridianal-plane….i.e. gives that noon-line an azimuth of zero.
>>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

I retract the addendum. I wrote it with the notion that the noon-line
should be under the style.   …as if the dial were intended to read for its
own longitude.

So, sorry—disregard the addendum (…as you probably already have).

The dial-plate’s rotation in its own plane should be to correct the style’s
pointing-direction (in altitude or azimuth), as I originally said &
described.

Correcting its altitude would give an easier equation-solution.



On Sat, Apr 8, 2023 at 21:25 Michael Ossipoff 
wrote:

> Addendum:
>
> …
>
> Instead of finding the dial-plate rotation in its own plane that corrects
> the style’s pointing-direction, it might be easier to, instead, find the
> dial-plate rotation in its own plane that puts the dial’s noon-line in the
> meridianal-plane….i.e. gives that noon-line an azimuth of zero.
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

For complete generality:

If your sundial was made for a latitude greater then yours by an amount
called “DeltaLat” (which could be positive or negative), & if you want the
dial to give LTST for a longitude 7 degrees west of yours (maybe because
that’s your standard-meridian), then:

After the tip, the initially-top-point of the sphere with a great-circle
coinciding with the circumference of your circular dial-plate will have
equatorial-coordinates of:

(Lat+DeltaLat, 7).

After that, it’s exactly as I said.





On Sun, Apr 9, 2023 at 14:09 Steve Lelievre 
wrote:

>
> On 2023-04-08 8:52 p.m., Michael Ossipoff wrote:
>
> I know you said you wanted a link, not instructions, but people have been
> suggesting how to achieve dial-autocorrection to Local True Solar Time
> (LTST) at the standard-meridian, instead of one’s own meridian. So I felt
> that it would be justified to comment about it.
>
> Michael,
>
> To me, your case seems to be a specific instance that is covered by the
> general case - have I missed something?
>
> As things stand, I think I know the math involved because I have from the
> article by Fred Sawyer that I mentioned in a previous email. It describes
> the solution for the general case - we start with a dial at some latitude
> and longitude that shows the solar time at some other longitude, which may
> or may not be zero offset. We want to move it to a new latitude and
> longitude and to show the solar time at some new 'other' longitude, which
> may or may not have zero offset from the new location. As well, the article
> by Fabio Savian, mentioned in his post, also discusses dial relocation.
> (BTW, for NASS members, Fabio only mentioned his article in its Italian
> version, but as well he kindly provided an English equivalent which was
> included in the most recent issue of the Compendium)
> Everyone,
>
> Since I'm writing this post, I'll take the opportunity to mention that I
> have made a couple of small adjustments to my online wedge calculator,
> gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it
> better for the southern hemisphere. Please let me know if you spot any
> issues.
>
>
> Steve
>
>
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

Yes, I spoke of a special-case in which you’re 7 degrees east of your
standard-meridian. …for a concrete example. But the rest of what I said was
for the general-case in which you want the dial to read in the LTST at your
standard-meridian.

But yes, I didn’t speak of when the dial is made for a different latitude
*and* you want standard-meridian LTST.

I thought that it was just about getting the standard- meridian LTST.
 …something I wouldn’t do anyway.

On Sun, Apr 9, 2023 at 14:09 Steve Lelievre 
wrote:

>
> On 2023-04-08 8:52 p.m., Michael Ossipoff wrote:
>
> I know you said you wanted a link, not instructions, but people have been
> suggesting how to achieve dial-autocorrection to Local True Solar Time
> (LTST) at the standard-meridian, instead of one’s own meridian. So I felt
> that it would be justified to comment about it.
>
> Michael,
>
> To me, your case seems to be a specific instance that is covered by the
> general case - have I missed something?
>
> As things stand, I think I know the math involved because I have from the
> article by Fred Sawyer that I mentioned in a previous email. It describes
> the solution for the general case - we start with a dial at some latitude
> and longitude that shows the solar time at some other longitude, which may
> or may not be zero offset. We want to move it to a new latitude and
> longitude and to show the solar time at some new 'other' longitude, which
> may or may not have zero offset from the new location. As well, the article
> by Fabio Savian, mentioned in his post, also discusses dial relocation.
> (BTW, for NASS members, Fabio only mentioned his article in its Italian
> version, but as well he kindly provided an English equivalent which was
> included in the most recent issue of the Compendium)
> Everyone,
>
> Since I'm writing this post, I'll take the opportunity to mention that I
> have made a couple of small adjustments to my online wedge calculator,
> gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it
> better for the southern hemisphere. Please let me know if you spot any
> issues.
>
>
> Steve
>
>
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Steve Lelievre]

On 2023-04-08 8:52 p.m., Michael Ossipoff wrote:


I know you said you wanted a link, not instructions, but people have 
been suggesting how to achieve dial-autocorrection to Local True Solar 
Time (LTST) at the standard-meridian, instead of one’s own meridian. 
So I felt that it would be justified to comment about it.



Michael,

To me, your case seems to be a specific instance that is covered by the 
general case - have I missed something?


As things stand, I think I know the math involved because I have from 
the article by Fred Sawyer that I mentioned in a previous email. It 
describes the solution for the general case - we start with a dial at 
some latitude and longitude that shows the solar time at some other 
longitude, which may or may not be zero offset. We want to move it to a 
new latitude and longitude and to show the solar time at some new 
'other' longitude, which may or may not have zero offset from the new 
location. As well, the article by Fabio Savian, mentioned in his post, 
also discusses dial relocation. (BTW, for NASS members, Fabio only 
mentioned his article in its Italian version, but as well he kindly 
provided an English equivalent which was included in the most recent 
issue of the Compendium)


Everyone,

Since I'm writing this post, I'll take the opportunity to mention that I 
have made a couple of small adjustments to my online wedge calculator, 
gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it 
better for the southern hemisphere. Please let me know if you spot any 
issues.


Steve


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

Re: Adjusting dial to new location

[Michael Ossipoff]

Addendum:

…

Instead of finding the dial-plate rotation in its own plane that corrects
the style’s pointing-direction, it might be easier to, instead, find the
dial-plate rotation in its own plane that puts the dial’s noon-line in the
meridianal-plane….i.e. gives that noon-line an azimuth of zero.
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

Steve—

…

I know you said you wanted a link, not instructions, but people have been
suggesting how to achieve dial-autocorrection to Local True Solar Time
(LTST) at the standard-meridian, instead of one’s own meridian. So I felt
that it would be justified to comment about it.

…

…even though that autocorrection wouldn’t bring any convenience for the
user, who’d still need a correction (for Eqt), & even though it would
create an inconvenience for anyone who wanted genuinely local LTST, because
they’d have to uncorrect the longitude-correction.

…

First I suggested solution of 3 simultaneous nonlinear equations, written
via coordinate-transformation formulas, with three unknown variables:
Initial horizontal dial-plate rotation about the vertical axis through its
center, the place on the dial-plate circumference for placing the wedge, &
the amount to tip the plate with that wedge.

…

…in order to get the style pointed at the celestial-pole, with the
noon-line in the meridianal-plane.  3 equations in 3 unknowns.

…

Undeniably that would solve the problem, but 3 nonlinear equations would be
a bit of work.  That work is unnecessary, because it can be solved
analytically.

…

I described how one could find how to tip the dial-plate:

…

1) The point at the top of the sphere having a great-circle that coincides
with the circumference of the dial-plate, has, in the
equatorial-coordinate-system,  a declination equal to the latitude of the
dial. It has an hour-angle (equatorial longitude) of zero.

…

2) Say you’re 7 degrees east of your standard meridian. Rotating the dial 7
degrees westward about the polar axis, the axis of the equatorial-system,
changes the top-point’s equatorial coordinates to (Lat, 7).

…

3) Transform those new equatorial coordinates to the horizontal coordinate
system, to get the altitude & azimuth of the top-point.

…

4) Place the wedge at the edge of the circular dial-plate 180 degrees from
the calculated azimuth of the top point.  Tip the dial-plate up, there, by
an angle equal to the complement of the calculated altitude of the
top-point.

…

Now the dial-plate is tipped as it would be if the dial had been rotated 7
degrees westward in equatorial-longitude, hour-angle,  about the polar-axis.
But the dial’s noon-line might not be in the meridianal-plane.

…

One way to fix that:

…

5) Rotate the dial-plate in the plane of the dial-face, until the dial
reads the correct LTST at the standard-meridian.

…

That would require carefully marking where the edge of the dial place is,
at several circumference-positions on the table-surfa ce, marking where the
wedge with respect to dial & table-surface, & marking where the dial-plate
touches the wedge.

…

Then lift the dial-plate a bit off the wedge & rotate the dial-plate in the
plane of its dial-surface, & set it back down, making sure that the
dial-plate & wedge are at their original marks.

…

Do that till the dial reads the LTST at the standard-meridian.

…

That dial-rotation sounds laborious & awkward, doing it after the tipping,
with all the position marking & keeping.   …especially with the wedge under
the dial-plate.

…

Another way:

…

6) Before the tipping, the style is pointing at the celestial-pole.
Transform that position to the get the pole’s pre-tip coordinates in the
coordinate system whose axis is a horizontal line perpendicular to the
direction in which the direction in which the dial is going to be tipped.  Now
add the complement of the calculated top-point-altitude to the longitude in
that system with the horizontal axis. That gives the style’s
pointing-direction’s new longitude in the system with the horizontal  tip-axis.
So now you have both of its new coordinates in that system.

…

7) Transform that position to either the horizontal (altazimuth)
coordinate-stem, to get the altitude & azimuth of the style’s new
pointing-direction…or instead to the equatorial-system to get the style’s
pointing-direction, as declination & hour-angle in the equatorial-system.

…

8) That tells you how much the style’s pointing-direction is off, in terms
of its altitude, or its azimuth, or its declination.   …whichever of those
you want to use.  Its azimuth should of course be zero. Its altitude should
of course equal your latitude, & its declination of course should be 90
degrees. The altitude is probably not a good choice to use, because it
changes more slowly with change in the dial plate rotation.  I’d probably
use the declination, because its formula is simpler than that of the
azimuth.

…

9) So, find out how much thequantity for the style’s pointing-direction
that you’re using, say the declination,  needs to change, to put it where
it should be. Another coordinate-transformation will tell you how much the
dial-plate would have to rotate in the plane of the dial-face, to achieve
that.  That’s the desired dial-plate-rotation.

…

10) So, before tipping,  you rotate the dial-plate in its own plane, by
that amount, before you 

Re: Adjusting dial to new location

[Michael Ossipoff]

 Contrary to what I suggested yesterday, the adjustment of a sundial to
give LTST at the standard-meridian doesn’t require solution of a system of
equations. It’s a straightforward coordinate-transformation:

…

Say the dial-plate is circular. For a sphere that circumscribes that
dial-plate, the equatorial-coordinates on the sphere, of a point at the top
of that sphere, are (Lat, 0).

...

…where Lat is the latitude of the dial’s location, & 0 is defined as the
longitude of the topmost meridian in the equatorial-system.

…

Now, say your location is 7 degrees east of your standard meridian. You
want to change the equatorial-coordinates of that top-point to (Lat, 7).

...

(…because let’s say that hour-angle (equatorial-longitude) is measured
clockwise (westward) from the NS meridian, as it normally is.)

…

That’s the top-points coordinates in the equatorial system when the sphere
has been rotated 7 degrees about its polar-axis, toward the
standard-meridian.

...

Now transform the top-point’s coordinates (Lat, 7) to the horizontal
coordinate-system.

…

That gives you the azimuth & altitude of the top-point, as seen from the
center of the sphere.

…

The dial-edge is a great circle on the sphere, all of which is 90 degrees
away from the former top-point.

…

The place on the dial-plate that should be raised is the place 180 degrees
from the top-point’s azimuth.

…
Raise that point by an angle equal to the complement of the altitude of the
top-point

On Sun, Mar 26, 2023 at 5:30 PM Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Michael Ossipoff]

[quote]

Assuming that a dial should read only local solar time is a rather limited
view.

[/quote]

…

:-)  What?

…

So, an expressed preference is a “limited view”?  :-)

…

LTST stands for Local-True-Solar-Time.

…

A dial that reads in LTST at your latitude *at your standard
meridian*…instead of *where the sundial is*, makes no sense.

…

It doesn’t make it any easier for viewers to obtain clock-time from the
dial.  That’s because, if the dial reads in your LTST, where the dial is,
then, when making the correction-table, the longitude-correction-constant
can just be added to every EqT entry, resulting in a combined-corrections
table.

…

Then, the user’s task, for converting from dial-time to standard time, is
exactly the same:  Add a correction from a correction-table.

…

In other words, making dial read in LTST at your standard-meridian, instead
of where the dial is, doesn’t make it any easier for the viewer to get
clock-time from the dial.

…

But what it DOES accomplish is that it makes it necessary to apply a
correction in order to get LTST (where you are) from the dial.

…

[quote]

While it might be of interest to the dial purist

[/quote]

…

LTST, Sundial-Time is the time-of-day that standard-time is based on &
approximated.  …but LTST is the real-thing.  A dial that reads in LTST is
telling you the actual time-of-day by the Sun.

…

For appointments, & catching a scheduled bus, train or flight, clock-time
is what matters. For the Sun’s time-of-day, LTST is what it’s about, & what
standard-time is merely a rough approximation of.

…

Yes, other kinds of hours have been used. Temporary Hours must have been
useful if you had some task that needed daylight, &, to evaluate your
progress in that task, it was helpful to know what fraction of the day has
elapsed. You’ve plowed ¾ of the field, & about ¾ of the day has elapsed, &
so you know that your progress is good.

…

Myself, I personally don’t like Temporary Hours, because I don’t want to be
told what fraction of the day has elapsed, because it sounds like negative
news. It seems to me that it emphasizes a negative interpretation of the
time-of-day.  Just my impression.

…

Co-Italian Hours can be very relevant, however, when it tells you how many
hours of daylight remain.  Better yet, I’d prefer being told how many hours
remained until the end of evening Civil-Twilight.

…

My next sundials will give French Hours (equal 15-degree hours) &
Co-Italian Hours (but hours till the end of evening Civil-Twilight instead
of Sunset).

…

Also, my next sundials will have declination-lines for the Solar
ecliptic-months (Aries-Pisces)., marked with the old symbols for those
ecliptic-months.  I’ll also add declination-lines for some days during the
waxing half of the year, when the Solar-Declination has gone significant
fractions of the way from its Winter-Solstice value to its Summer-Solstice
value.   …&, additionally, declination-lines for the ancient Celtic
cross-quarter seasonal-holidays.

…

[quote]

it is not particularly useful to the general population

[/quote]

…

News-flash:  People nowadays take pleasure from, & admire sundials for
reasons other than practical-need.

…

Sundials are liked & looked-at & read because of their beauty & their
natural significance, directly showing nature’s time, the Sun’s own time,
based on where the Sun actually is.   …not clock-time.

…

As I mentioned, LTST is what standard-time is based on & approximates…but
LTST is the real-thing. The genuine natural Solar time-of-day…the kind
expressed in equal 15-degree hours.

…

Clock time can indeed be important, when you have an appointment, meeting
job deadline, or must catch a bus, train or plane, etc.  That just isn’t
part of what people like about sundials.

…

As I’ve mentioned, I used to use & carry a tablet-dial, when reliable
accurate watches were expensive. It had a combined
longitude-correction-constant + Eqt, on the top of the closed tablet. One
single correction-table for the combined correction.

…

[quote]

 and often requires a lot of explanation.

[/quote]

…

How hard is it to tell someone that the Sundial tells the time based on
where the Sun is, as opposed to clock-time, which has less relation to the
Sun’s time.

…

A Sundial that reads directly in the LTST where you are doesn’t need any
correction for that.

…

Getting clock-time from a sundial that reads directly in the LTST at your
standard-meridian needs the EqT correction to be applied, to get
standard-time.   …but also needs a correction to be applied to get your
LTST where the dial is.

…

So which is really simpler?.

…

[quote]

And it makes us seem like an eccentric clique.

[/quote]

…

People don’t come over  & look at a Sundial because they want clock-time
from it. They like its beauty & its Solar nature significance, when it
directly tells them the time based on where the Sun is, Sun’s time,
nature’s time.

…

[quote]

The dial produces a shadow. The hour lines and other indications are

Re: Adjusting dial to new location

[Michael Ossipoff]

By “auto-correction”, I refer modification of the dial, so that it will
directly read Local-True-Solar-Time (LTST) at your latitude at your
standard-meridian instead of where the dial is.

…

Auto-correcting for longitude by rotating & tipping the dial is a
“retrofit” longitude auto-correction, as opposed to initially incorporating
that auto-correction in the marking of the dial.

…

(As I said, I have no idea why anyone would want longitude-auto-correction,
to make the dial read the Local-True-Solar-Time (LTST) at your latitude at
your timezone’s standard-meridian (instead of where the dial is). Because
the longitude-correction could be achieved by merely adding the
longitude-correction constant to each EqT entry on the correction-plaque,
the auto-correction doesn’t avoid any table-consulting & correction work
needed by the dial-user who wants standard-time.  All it accomplishes is to
make LTST determination require a correction too.)

…

As has already been pointed out twice, only one wedge is needed.

…

The longitude-correction could be achieved by, first, an initial rotation
about the vertical axis, & then a rotation about some particular horizontal
axis.

…

Three variables:

…

1. The amount & direction of initial rotation, about the vertical-axis,
away from the NS alignment of the gnomon.

…

2. The place on the circular-dial-plate’s circumference at which the wedge
is applied.

…

3. The amount by which the dial-plate is tipped by that wedge.

…

There are three desiderata:

…

1. The style is in the meridianal-plane, with its higher end poleward.

…

2.The Style is tipped above the horizontal by an angle equal to the
latitude.

…

3. The dial has been rotated about the style so as to have the orientation
of flat ground at your standard-parallel.at your latitude. (i.e. rotated in
the direction of your standard meridian, by the number of degrees by which
that meridian differs from yours.)

…

Those 3 desiderata give 3 equations in 3 unknowns. The 3 variable are the
unknowns.

…

The equations are spherical co-ordinate-transformation formulas. The 3
equation are statements, in terms of those formulas, that the 3 desiderata
are achieved.

…

The 3 nonlinear equations in 3 unknowns can be numerically-solved by the
Newton-Raphson method,  In fact according to some authors, Newton-Raphson
is the only method available for a system  of nonlinear equations.

…

You speak of rotation about 3 axes. …2 of them by wedges?  (…because you’ve
suggested 2 wedges.).

,,,

When the 1st wedge is put in at (say) the dial-plate’s north edge, the dial
plate is supported by, & stably balanced on, the wedge at the dial-plate’s
north edge, & the dial edge opposite the wedge, at the south edge of the
dial-plate. That means that the whole dial-plate & all of its periphery
(except its south-point) are above the horizontal table-surface on which
the dial was resting.

…

Now, when you put a 2nd wedge in at (say) the dial-plate’s east edge, &
push it in till it contacts the raised dial-edge, & then & start rotating
the dial-plate with it, about what axis are you rotating the
dial-plate?  You’re
rotating it about the line drawn between the point at the dial-plate’s
south edge, where the dial-plate rests on its horizontal table, & some
point on the west edge of the wedge at the north end of the dial.

…

That isn’t a horizontal axis.

…

I guess you could do it that way, but it sounds like more work than the use
of just one wedge.

…

As I said, you only need one wedge.

…

Your other suggestion expressed after that is unclear.

On Tue, Apr 4, 2023 at 7:38 PM  wrote:

> Depending on your choice of rotation axes, only two rotations are needed,
> one for the elevation of the pole and one around the gnomon for longitude
> correction. These are the two that correspond to the actual changes needed.
>
> If you are using the three orthogonal x, y, and z axes, then three
> rotations are needed. And they can tell you how to make the wedge.
>
> Another three rotation procedure that might be easier to understand but
> may not tell you how to make the wedge is this. Rotate about a horizontal
> axis until the gnomon is vertical. Now rotate around the vertical axis to
> include the longitude correction. Then rotate around a horizontal axis to
> put the gnomon in the correct new location. I would do this in a computer
> graphics situation because it only requires the old and new position values.
> ---
>
>
>
> On 2023-04-04 15:54, Steve Lelievre wrote:
>
>
> At a new location, a dial must end up with the style parallel to the polar
> axis - but how do you achieve that using a wedge? Assuming you start with
> the dial at the new location on a horizontal surface with the sub-stile
> line on the local meridian, the required sequence is to rotate it about the
> local vertical, then about an east-west line, and then about the vertical
> again. Perhaps this helps visualize it... https://youtu.be/mtEgSXJPXSw
>
> The wedge achieves the same thing 

Re: Adjusting dial to new location

[koolish]

Depending on your choice of rotation axes, only two rotations are
needed, one for the elevation of the pole and one around the gnomon for
longitude correction. These are the two that correspond to the actual
changes needed. 


If you are using the three orthogonal x, y, and z axes, then three
rotations are needed. And they can tell you how to make the wedge. 


Another three rotation procedure that might be easier to understand but
may not tell you how to make the wedge is this. Rotate about a
horizontal axis until the gnomon is vertical. Now rotate around the
vertical axis to include the longitude correction. Then rotate around a
horizontal axis to put the gnomon in the correct new location. I would
do this in a computer graphics situation because it only requires the
old and new position values.

---

On 2023-04-04 15:54, Steve Lelievre wrote:

At a new location, a dial must end up with the style parallel to the polar axis - but how do you achieve that using a wedge? Assuming you start with the dial at the new location on a horizontal surface with the sub-stile line on the local meridian, the required sequence is to rotate it about the local vertical, then about an east-west line, and then about the vertical again. Perhaps this helps visualize it... https://youtu.be/mtEgSXJPXSw 

The wedge achieves the same thing because the twisting of the dial on the wedge face corresponds to the first rotation about a vertical, it's tip angle corresponds to the east-west rotation, and the turning of the wedge corresponds to the second rotation about the vertical. 

Steve 

On 2023-04-04 11:59 a.m., Rod Wall wrote: 


As Michael indicated in his email below: Rotating the whole dial around the 
polar axis is the correct way. to adjust a local solar time dial to a different 
longitude


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

Re: Adjusting dial to new location

[koolish]

Assuming that a dial should read only local solar time is a rather
limited view. While it might be of interest to the dial purist, it is
not particularly useful to the general population and often requires a
lot of explanation. And it makes us seem like an eccentric clique. The
dial produces a shadow. The hour lines and other indications are
strictly our interpretation and a particular one should not be forced on
everybody else.

---

On 2023-04-04 13:05, Michael Ossipoff wrote:

On Tue, Apr 4, 2023 at 08:45  wrote: 

Rotating the dial plate around a vertical axis is wrong because the hours lines are not at constant angles. 

Rotating the whole dial around the polar axis is the correct way to adjust a local solar time dial to a different longitude, the time zone center, for example. 


Having a dial show the time in a different location is strictly a creative 
choice.

---

Rotating the dial about the vertical axis & then doing the non-meridian Al 
tipping, in the right combination, is how you get the result that the dial is 
oriented (still in the meridianal-plane) to give Local True Solar Time at your 
standard meridian.


I don't know why anyone would want to do that, unless it's important to keep using an old EqT plaque. 

On 2023-04-04 08:44, Jack Aubert via sundial wrote: 
Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die

eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment. 
---

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Re: Adjusting dial to new location

[Steve Lelievre]

At a new location, a dial must end up with the style parallel to the 
polar axis - but how do you achieve that using a wedge? Assuming you 
start with the dial at the new location on a horizontal surface with the 
sub-stile line on the local meridian, the required sequence is to rotate 
it about the local vertical, then about an east-west line, and then 
about the vertical again. Perhaps this helps visualize it... 
https://youtu.be/mtEgSXJPXSw


The wedge achieves the same thing because the twisting of the dial on 
the wedge face corresponds to the first rotation about a vertical, it's 
tip angle corresponds to the east-west rotation, and the turning of the 
wedge corresponds to the second rotation about the vertical.


Steve


On 2023-04-04 11:59 a.m., Rod Wall wrote:


As Michael indicated in his email below: *Rotating the whole dial 
around the polar axis is the correct way. *to adjust a local solar 
time dial to a different longitude


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

Fwd: Adjusting dial to new location

[Michael Ossipoff]

-- Forwarded message -
From: Michael Ossipoff 
Date: Tue, Apr 4, 2023 at 09:53
Subject: Re: Adjusting dial to new location
To: 


The combination of rotation about the vertical axis, &  then non-meridianal
tipping, hadn’t occurred to me.

…to directly read the Local True Solar Time of somewhere else.

…so that you can just use your old EqT plaque after you move?

Wouldn’t have occurred to me. I’d just make a table incorporating EqT & the
new longitude- correction.

I wouldn’t want a sundial to be committed to clock-time, by building in the
longitude correction (either when marking the dial, or by the rotation &
tipping).


On Tue, Apr 4, 2023 at 08:45  wrote:

> Rotating the dial plate around a vertical axis is wrong because the hours
> lines are not at constant angles.
>
> Rotating the whole dial around the polar axis is the correct way to adjust
> a local solar time dial to a different longitude, the time zone center, for
> example.
>
> Having a dial show the time in a different location is strictly a creative
> choice.
> ---
>
>
>
> On 2023-04-04 08:44, Jack Aubert via sundial wrote:
>
> Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
> eigentliche Nachricht steht dadurch in einem Anhang.
>
> This message was wrapped to be DMARC compliant. The actual message
> text is therefore in an attachment.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Adjusting dial to new location

[Michael Ossipoff]

The public stationary sundial in my town is mounted normally for Local True
Solar Time. It’s correction-plaque gives un-adjusted EqT, with an
instruction to add a certain number of minutes for the longitude-correction.

On Sun, Apr 2, 2023 at 17:26 Steve Lelievre 
wrote:

> You don’t need two wedges, you just skew the positioning to do both
> adjustments in one.
>
> If you have The Compendium vol 7 issue 1, take a look at the articles by
> Fred Sawyer and Bill Gottesman.
>
> Steve
>
> On Sun, Apr 2, 2023 at 17:20, Rod Wall  wrote:
>
>> Hi Jack and Steve,
>>
>> To implement what Jack has indicated. You could have two wedges one on
>> top of each other. One for Latitude correction and one for Longitude
>> correction.
>>
>> You could also just use a Longitude correction wedge if you only wanted
>> to correct for Longitude.
>>
>> When writing instructions. Please also include people who live in the
>> southern hemisphere, we do also have sundials.
>>
>> Do I have this correct?
>>
>> Roderick.
>>
>> On 3/04/2023 9:24 am, Steve Lelievre wrote:
>>
>> Jack,
>>
>> Try out my calculator! You can specify a time zone meridian for the dial
>> at its original location, or at its new location, or both. If there is an
>> effective longitude change, it'll tell you how to position (twist) the dial
>> on the wedge and how to orient the wedge itself, turning it away (rotating
>> it ) from the meridian line.
>>
>> Steve
>>
>>
>> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>>
>> I thought about this briefly.  I had always thought that the purpose of
>> the shim or wedge adjustment was to tip the dial north or south so that
>> dial is at the latitude it was originally designed for.  If the original
>> dial has a built-in longitude correction, that could also be factored into
>> a wedge which would have both a north-south and east-west axis.  But a
>> wedge would not work if it moved the gnomon out of alignment with the with
>> the rotation of the earth (or the celestial sphere).  I think a
>> longitudinal adjustment would only work if he original dial had a time-zone
>> offset included by rotating the hour lines with respect to the origin of
>> the gnomon.
>>
>>
>>
>> Does this make sense?  It sounds like a good project for a 3-D printer.
>>
>>
>>
>> Jack
>>
>>
>>
>> *From:* sundial 
>>  *On Behalf Of *Steve Lelievre
>> *Sent:* Sunday, April 2, 2023 5:16 PM
>> *To:* Michael Ossipoff  
>> *Cc:* Sundial List  
>> *Subject:* Re: Adjusting dial to new location
>>
>>
>>
>> Michael,
>>
>> Yes, I recognize that to get Mean Time involves Equation of Time
>> adjustment and that Equation of Longitude can be handled there to give
>> Standard Time (or DST).
>>
>> But anyway, my inquiry was to seek an online wedge calculator. Nobody
>> identified one and  a week seemed an adequate wait for responses, so I've
>> just written one.  Anyone who's interested, please see
>>
>>
>> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>>
>> Cheers,
>>
>> Steve
>>
>>
>>
>> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>>
>> I just want to mention that the shim under the north or south edge of the
>> dial is only for latitude. Longitude is corrected-for by changing the
>> constant term of the Sundial-Time to Clock-Time conversion.
>>
>>
>>
>> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
>> sundial.
>>
>>
>>
>> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
>> steve.lelievre.can...@gmail.com> wrote:
>>
>> Hi,
>>
>> Can anyone point me to an existing online calculator for making a wedge
>> to adjust a horizontal dial to a new latitude and longitude?
>>
>> I am not asking for an explanation of how to do the calculation; I just
>> want to be able to point people to a calculator that has already been
>> proved on the internet. It should use the original location (latitude
>> and longitude) and the new location to calculate the angle of slope of
>> the wedge and the required rotation from the meridian.
>>
>> Many thanks,
>>
>> Steve
>>
>>
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
>> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>> --
> Cell +1 778 837 5771
> ---
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>
>
---
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Re: Adjusting dial to new location

[Michael Ossipoff]

On Tue, Apr 4, 2023 at 08:45  wrote:

> Rotating the dial plate around a vertical axis is wrong because the hours
> lines are not at constant angles.
>
> Rotating the whole dial around the polar axis is the correct way to adjust
> a local solar time dial to a different longitude, the time zone center, for
> example.
>
> Having a dial show the time in a different location is strictly a creative
> choice.
> ---
>
>
> Rotating the dial about the vertical axis & then doing the non-meridian Al
> tipping, in the right combination, is how you get the result that the dial
> is oriented (still in the meridianal-plane) to give Local True Solar Time
> at your standard meridian.
>

I don’t know why anyone would want to do that, unless it’s important to
keep using an old EqT plaque.

> On 2023-04-04 08:44, Jack Aubert via sundial wrote:
>
> Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
> eigentliche Nachricht steht dadurch in einem Anhang.
>
> This message was wrapped to be DMARC compliant. The actual message
> text is therefore in an attachment.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

Rotating the dial plate around a vertical axis is wrong because the
hours lines are not at constant angles. 


Rotating the whole dial around the polar axis is the correct way to
adjust a local solar time dial to a different longitude, the time zone
center, for example. 


Having a dial show the time in a different location is strictly a
creative choice.

---

On 2023-04-04 08:44, Jack Aubert via sundial wrote:


Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment. 
---

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

RE: Adjusting dial to new location

[Jack Aubert via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment.--- Begin Message ---
I think I must be missing something here.  I cannot quite wrap my brain around 
what we would be trying to accomplish with a longitude adjustment.

 

A horizontal garden variety dial should tell apparent local solar time as long 
as it is correctly designed and the gnomon is pointing at the north celestial 
pole.  It can be moved to a new location and will continue to tell apparent 
local solar time as long as the whole thing is tilted so that it is at the 
latitude it was designed for and positioned so that the gnomon continues to 
point to the north celestial pole.  Now, If such a dial were to be tilted on 
its other axis so that it corresponds to the original longitude then I think it 
would tell local solar time at the original longitude.  This would appear to be 
wrong since it would not correspond to either local solar time or local civil 
time.   

 

AFAIK, the only way longitude comes into play in the design would be to make 
the dial conform more closely to civil time (leaving aside the equation of 
time) for example if the dial is located near the edge of the time zone.  AFAIK 
the only way to do this is to shift the dial plate around the vertical axis 
originating at the bottom end of the gnomon so that noon is no longer lined up 
with the gnomon and east west are no longer at right angles to the gnomon.  If 
such a dial were relocated then it would need some kind of longitude adjustment 
but would it not then tell something approximating civil time at its old 
location rather than the new one?

 

Is this wrong?  Is it possible to make a local longitude adjustment by tilting 
the whole thing on its polar axis?  

 

My spherical trig is almost nonexistent so I am trying to imagine all this 
visually and cannot quite see how it would work.  It seems to me that an 
east-west wedge would throw the gnomon off its polar axis.  

 

Jack Aubert  

 

 

From: sundial  On Behalf Of Steve Lelievre
Sent: Monday, April 3, 2023 7:47 PM
To: Rod Wall ; kool...@dickkoolish.com
Cc: 'Sundial sundiallist' 
Subject: Re: Adjusting dial to new location

 

Hi, Roderick,

My home internet connection is still non-functional so I can't fix it yet, but 
it does seem that I will have to add an extra test to handle southern 
hemisphere locations and reducing latitudes. Actually, I originally had a 
southern hemisphere check in there but took it out after convincing myself the 
same frame of reference (x axis east, y axis north, z up) applied to the 
spherical trigonometry irrespective of hemisphere. Ho hum.

Steve

 

On 2023-04-03 6:45 a.m., Rod Wall wrote:

Hi Steve,

For both examples below with all sundials at the same Longitude. The 
instructions indicate: 

Place the wedge-sundial assembly on a horizontal surface in a nice sunny 
location. Start with the higher end of the wedge to the north and the sides 
aligned on a north-south line and the sharp edge should be on an east-west line.

Example 1:



If you have a sundial that was designed for Latitude -20 deg. And relocate it 
at Latitude -50 deg.

Would you start with the higher end of the 30 deg wedge to the North. Or would 
it be to the South?



*

Example 2:



If you have a sundial that was designed for Latitude 50 deg. And relocate it at 
20 deg. 



Would you start with the higher end of the 30 deg wedge to the North. Or would 
it be to the South?

*



Please correct me if I am wrong. I think that both examples would be to the 
South.



Roderick.



 

--- End Message ---
---
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Re: Adjusting dial to new location

[Rod Wall]

Hi Steve,

I use to be a member of the NASS but I am retired now. And due to funds 
I was not able to renew my membership. So I don't have access to Fred 
Sawyer's and Bill Gottesman's article.


Maybe the Article and the drawing of the Earth with sundials could be 
used to explain this?


Roderick.

On 3/04/2023 10:26 am, Steve Lelievre wrote:
You don’t need two wedges, you just skew the positioning to do both 
adjustments in one.


If you have The Compendium vol 7 issue 1, take a look at the articles 
by Fred Sawyer and Bill Gottesman.


Steve

On Sun, Apr 2, 2023 at 17:20, Rod Wall  wrote:

Hi Jack and Steve,

To implement what Jack has indicated. You could have two wedges
one on top of each other. One for Latitude correction and one for
Longitude correction.

You could also just use a Longitude correction wedge if you only
wanted to correct for Longitude.

When writing instructions. Please also include people who live in
the southern hemisphere, we do also have sundials.

Do I have this correct?

Roderick.

On 3/04/2023 9:24 am, Steve Lelievre wrote:


Jack,

Try out my calculator! You can specify a time zone meridian for
the dial at its original location, or at its new location, or
both. If there is an effective longitude change, it'll tell you
how to position (twist) the dial on the wedge and how to orient
the wedge itself, turning it away (rotating it ) from the
meridian line.

Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:


I thought about this briefly.  I had always thought that the
purpose of the shim or wedge adjustment was to tip the dial
north or south so that dial is at the latitude it was originally
designed for.  If the original dial has a built-in longitude
correction, that could also be factored into a wedge which would
have both a north-south and east-west axis.  But a wedge would
not work if it moved the gnomon out of alignment with the with
the rotation of the earth (or the celestial sphere).  I think a
longitudinal adjustment would only work if he original dial had
a time-zone offset included by rotating the hour lines with
respect to the origin of the gnomon.

Does this make sense?  It sounds like a good project for a 3-D
printer.

Jack

*From:* sundial 
<mailto:sundial-boun...@uni-koeln.de> *On Behalf Of *Steve Lelievre
*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff 
<mailto:email9648...@gmail.com>
*Cc:* Sundial List 
<mailto:sundial@uni-koeln.de>
    *Subject:* Re: Adjusting dial to new location

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time
adjustment and that Equation of Longitude can be handled there
to give Standard Time (or DST).

But anyway, my inquiry was to seek an online wedge calculator.
Nobody identified one and  a week seemed an adequate wait for
responses, so I've just written one.  Anyone who's interested,
please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or
south edge of the dial is only for latitude. Longitude is
corrected-for by changing the constant term of the
Sundial-Time to Clock-Time conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d
want from a sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre
 wrote:

Hi,

Can anyone point me to an existing online calculator for
making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the
calculation; I just
want to be able to point people to a calculator that has
already been
proved on the internet. It should use the original
location (latitude
and longitude) and the new location to calculate the
angle of slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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Re: Adjusting dial to new location

[Rod Wall]

Hi all,

Is the Sundial Mailing list able to accept images?

Below is how we can understand how sundials work. A sundial is a 
mechanical clock. Sundials are geared to the largest clock in the world, 
Earth. Look at it from a mechanical point of view on a spinning Earth.


Draw the earth and cut out paper sundials and place them at different 
Longitudes and see what wedge is needed to keep the style parallel to 
the axis of the Earth.


You can also understand how sundials work in the southern hemisphere. 
The sun still comes up in the East and sets in the West.


Roderick.

On 4/04/2023 12:03 pm, Michael Ossipoff wrote:
That surprises me too. I’d have expected that the only differences 
would be that the dial is numbered counterclockwise, & that north & & 
south are replaced with poleward & equatorward.


On Mon, Apr 3, 2023 at 16:47 Steve Lelievre 
 wrote:


Hi, Roderick,

My home internet connection is still non-functional so I can't fix
it yet, but it does seem that I will have to add an extra test to
handle southern hemisphere locations and reducing latitudes.
Actually, I originally had a southern hemisphere check in there
but took it out after convincing myself the same frame of
reference (x axis east, y axis north, z up) applied to the
spherical trigonometry irrespective of hemisphere. Ho hum.

Steve


On 2023-04-03 6:45 a.m., Rod Wall wrote:


Hi Steve,

For both examples below with all sundials at the same Longitude.
The instructions indicate:

Place the wedge-sundial assembly on a horizontal surface in a
nice sunny location. *Start with the higher end of the wedge to
the north* and the sides aligned on a north-south line and the
sharp edge should be on an east-west line.

Example 1:

If you have a sundial that was designed for Latitude -20 deg. And
relocate it at Latitude -50 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And
relocate it at 20 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Please correct me if I am wrong. I think that both examples would
be to the South.

Roderick.



---
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---
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Re: Adjusting dial to new location

[Rod Wall]

Hi all,

This link I think is a good way of showing. How we can understand how 
sundials work. A sundial is a mechanical clock. Sundials are geared to 
the largest clock in the world, Earth. Look at it from a mechanical 
point of view on a spinning Earth.


Draw the earth and cut out paper sundials and place them at different 
Longitudes and see what wedge is needed to keep the style parallel to 
the axis of the Earth.


https://www.dropbox.com/s/5loieb818s2dr9o/CCF%20Relocating%20a%20sundial%204%20April%202023.pdf?dl=0

You can also understand how sundials work in the southern hemisphere. 
The sun still comes up in the East and sets in the West.


Roderick

On 4/04/2023 12:03 pm, Michael Ossipoff wrote:
That surprises me too. I’d have expected that the only differences 
would be that the dial is numbered counterclockwise, & that north & & 
south are replaced with poleward & equatorward.


On Mon, Apr 3, 2023 at 16:47 Steve Lelievre 
 wrote:


Hi, Roderick,

My home internet connection is still non-functional so I can't fix
it yet, but it does seem that I will have to add an extra test to
handle southern hemisphere locations and reducing latitudes.
Actually, I originally had a southern hemisphere check in there
but took it out after convincing myself the same frame of
reference (x axis east, y axis north, z up) applied to the
spherical trigonometry irrespective of hemisphere. Ho hum.

Steve


On 2023-04-03 6:45 a.m., Rod Wall wrote:


Hi Steve,

For both examples below with all sundials at the same Longitude.
The instructions indicate:

Place the wedge-sundial assembly on a horizontal surface in a
nice sunny location. *Start with the higher end of the wedge to
the north* and the sides aligned on a north-south line and the
sharp edge should be on an east-west line.

Example 1:

If you have a sundial that was designed for Latitude -20 deg. And
relocate it at Latitude -50 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And
relocate it at 20 deg.

Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?

*

Please correct me if I am wrong. I think that both examples would
be to the South.

Roderick.



---
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---
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Re: Adjusting dial to new location

[Michael Ossipoff]

That surprises me too. I’d have expected that the only differences would be
that the dial is numbered counterclockwise, & that north & & south are
replaced with poleward & equatorward.

On Mon, Apr 3, 2023 at 16:47 Steve Lelievre 
wrote:

> Hi, Roderick,
>
> My home internet connection is still non-functional so I can't fix it yet,
> but it does seem that I will have to add an extra test to handle southern
> hemisphere locations and reducing latitudes. Actually, I originally had a
> southern hemisphere check in there but took it out after convincing myself
> the same frame of reference (x axis east, y axis north, z up) applied to
> the spherical trigonometry irrespective of hemisphere. Ho hum.
>
> Steve
>
>
> On 2023-04-03 6:45 a.m., Rod Wall wrote:
>
> Hi Steve,
>
> For both examples below with all sundials at the same Longitude. The
> instructions indicate:
>
> Place the wedge-sundial assembly on a horizontal surface in a nice sunny
> location. *Start with the higher end of the wedge to the north* and the
> sides aligned on a north-south line and the sharp edge should be on an
> east-west line.
>
> Example 1:
>
> If you have a sundial that was designed for Latitude -20 deg. And relocate
> it at Latitude -50 deg.
>
> Would you start with the higher end of the 30 deg wedge to the North. Or
> would it be to the South?
>
> *
>
> Example 2:
>
> If you have a sundial that was designed for Latitude 50 deg. And relocate
> it at 20 deg.
>
> Would you start with the higher end of the 30 deg wedge to the North. Or
> would it be to the South?
>
> *
>
> Please correct me if I am wrong. I think that both examples would be to
> the South.
>
> Roderick.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
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Re: Adjusting dial to new location

[Steve Lelievre]

Hi, Roderick,

My home internet connection is still non-functional so I can't fix it 
yet, but it does seem that I will have to add an extra test to handle 
southern hemisphere locations and reducing latitudes. Actually, I 
originally had a southern hemisphere check in there but took it out 
after convincing myself the same frame of reference (x axis east, y axis 
north, z up) applied to the spherical trigonometry irrespective of 
hemisphere. Ho hum.


Steve


On 2023-04-03 6:45 a.m., Rod Wall wrote:


Hi Steve,

For both examples below with all sundials at the same Longitude. The 
instructions indicate:


Place the wedge-sundial assembly on a horizontal surface in a nice 
sunny location. *Start with the higher end of the wedge to the north* 
and the sides aligned on a north-south line and the sharp edge should 
be on an east-west line.


Example 1:

If you have a sundial that was designed for Latitude -20 deg. And 
relocate it at Latitude -50 deg.


Would you start with the higher end of the 30 deg wedge to the North. 
Or would it be to the South?


*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And 
relocate it at 20 deg.


Would you start with the higher end of the 30 deg wedge to the North. 
Or would it be to the South?


*

Please correct me if I am wrong. I think that both examples would be 
to the South.


Roderick.

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

Fwd: Adjusting dial to new location

[Michael Ossipoff]

-- Forwarded message -
From: 
Date: Mon, Apr 3, 2023 at 07:35
Subject: Re: Adjusting dial to new location
To: Michael Ossipoff 


Local Solar Time is one of the things that a dial can do. But I might want
Time Zone time. Or I might want Paris France time. A dial can do both with
a longitude correction.


When making a sundial intended for use at just one location (e.g. a
stationary dial or a portable tablet horizontal dial), I combine EqT &
longitude correction into a single correction-table.

When all watches were mechanical, & reliable accurate ones were expensive,
I used to carry & use a tablet dial, made of corrugated box-cardboard,
aligned with a compass embedded in the dial-face.  With the
combined-correction on the top of the closed tablet-dial.
---



On 2023-04-02 21:40, Michael Ossipoff wrote:



On Sun, Apr 2, 2023 at 18:31  wrote:

I tried the app. I used 40, -75 and 45, -70. It just said to use a 5 degree
wedge and said nothing about a longitude correction.

I communicated to Steve privately last week. I said that a longitude
correction was a rotation around the gnomon. Does anybody else believe
this? One of the books, I can't remember which, calls this The Universal
Sundial Principle. It says that two dials with the same orientation in
space with respect to the sun will read the same time, regardless of where
on earth they are.


Yes, & if you want Local True Solar Time, then you don't need longitude
correction or Equation of Time.
---
 If you want clock-time, then use the EqT, & add 4 minutes for each degree
west of your standard meridian.


But isn't Sundial Time (Local True Solar Time) what you want from a sundial?





On 2023-04-02 19:24, Steve Lelievre wrote:

Jack,

Try out my calculator! You can specify a time zone meridian for the dial at
its original location, or at its new location, or both. If there is an
effective longitude change, it'll tell you how to position (twist) the dial
on the wedge and how to orient the wedge itself, turning it away (rotating
it ) from the meridian line.

Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:

I thought about this briefly.  I had always thought that the purpose of the
shim or wedge adjustment was to tip the dial north or south so that dial is
at the latitude it was originally designed for.  If the original dial has a
built-in longitude correction, that could also be factored into a wedge
which would have both a north-south and east-west axis.  But a wedge would
not work if it moved the gnomon out of alignment with the with the rotation
of the earth (or the celestial sphere).  I think a longitudinal adjustment
would only work if he original dial had a time-zone offset included by
rotating the hour lines with respect to the origin of the gnomon.



Does this make sense?  It sounds like a good project for a 3-D printer.



Jack



*From:* sundial 
 *On Behalf Of *Steve Lelievre
*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff  
*Cc:* Sundial List  
*Subject:* Re: Adjusting dial to new location


Michael,

Yes, I recognize that to get Mean Time involves Equation of Time adjustment
and that Equation of Longitude can be handled there to give Standard Time
(or DST).

But anyway, my inquiry was to seek an online wedge calculator. Nobody
identified one and  a week seemed an adequate wait for responses, so I've
just written one.  Anyone who's interested, please see

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve


On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south edge of the
dial is only for latitude. Longitude is corrected-for by changing the
constant term of the Sundial-Time to Clock-Time conversion.


But usually Sundial-Time, Local True Solar Time, is what I'd want from a
sundial.


On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

Hi,

Can anyone point me to an existing online calculator for making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the calculation; I just
want to be able to point people to a calculator that has already been
proved on the internet. It should use the original location (latitude
and longitude) and the new location to calculate the angle of slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


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


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


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

Fwd: Adjusting dial to new location

[Michael Ossipoff]

-- Forwarded message -
From: Michael Ossipoff 
Date: Mon, Apr 3, 2023 at 14:12
Subject: Re: Adjusting dial to new location
To: 


Of course, but I’d always make the dial to directly show Local True Solar
Time. I’d never incorporate a built-in longitude correction.

My use of EqT & longitude- correction constant is only for:

1. Aligning the dial by use of a clock or watch

2. Getting  Local True Solar Time from a clock or watch

3. Determine the clock-time of a sunset, end of evening civil-twilight, or
beginning of morning nautical-twilight

On Mon, Apr 3, 2023 at 07:35  wrote:

> Local Solar Time is one of the things that a dial can do. But I might want
> Time Zone time. Or I might want Paris France time. A dial can do both with
> a longitude correction.
>
>
> ---
>
>
>
> On 2023-04-02 21:40, Michael Ossipoff wrote:
>
>
>
> On Sun, Apr 2, 2023 at 18:31  wrote:
>
> I tried the app. I used 40, -75 and 45, -70. It just said to use a 5
> degree wedge and said nothing about a longitude correction.
>
> I communicated to Steve privately last week. I said that a longitude
> correction was a rotation around the gnomon. Does anybody else believe
> this? One of the books, I can't remember which, calls this The Universal
> Sundial Principle. It says that two dials with the same orientation in
> space with respect to the sun will read the same time, regardless of where
> on earth they are.
>
>
> Yes, & if you want Local True Solar Time, then you don't need longitude
> correction or Equation of Time.
> ---
>  If you want clock-time, then use the EqT, & add 4 minutes for each degree
> west of your standard meridian.
>
>
> But isn't Sundial Time (Local True Solar Time) what you want from a
> sundial?
>
>
>
>
>
> On 2023-04-02 19:24, Steve Lelievre wrote:
>
> Jack,
>
> Try out my calculator! You can specify a time zone meridian for the dial
> at its original location, or at its new location, or both. If there is an
> effective longitude change, it'll tell you how to position (twist) the dial
> on the wedge and how to orient the wedge itself, turning it away (rotating
> it ) from the meridian line.
>
> Steve
>
>
> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>
> I thought about this briefly.  I had always thought that the purpose of
> the shim or wedge adjustment was to tip the dial north or south so that
> dial is at the latitude it was originally designed for.  If the original
> dial has a built-in longitude correction, that could also be factored into
> a wedge which would have both a north-south and east-west axis.  But a
> wedge would not work if it moved the gnomon out of alignment with the with
> the rotation of the earth (or the celestial sphere).  I think a
> longitudinal adjustment would only work if he original dial had a time-zone
> offset included by rotating the hour lines with respect to the origin of
> the gnomon.
>
>
>
> Does this make sense?  It sounds like a good project for a 3-D printer.
>
>
>
> Jack
>
>
>
> *From:* sundial 
>  *On Behalf Of *Steve Lelievre
> *Sent:* Sunday, April 2, 2023 5:16 PM
> *To:* Michael Ossipoff  
> *Cc:* Sundial List  
> *Subject:* Re: Adjusting dial to new location
>
>
> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
>
> But usually Sundial-Time, Local True Solar Time, is what I'd want from a
> sundial.
>
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the 

Fwd: Adjusting dial to new location

[Michael Ossipoff]

-- Forwarded message -
From: Michael Ossipoff 
Date: Mon, Apr 3, 2023 at 14:04
Subject: Re: Adjusting dial to new location
To: Rod Wall 


Yes, because you’ve moved the dial south, you tip it south.

The wedge-use is as you say, but I’d prefer a flat, vertical-edge shim,
because it wouldn’t experience a force tending to push it out.

On Mon, Apr 3, 2023 at 06:45 Rod Wall  wrote:

> Hi Steve,
>
> For both examples below with all sundials at the same Longitude. The
> instructions indicate:
>
> Place the wedge-sundial assembly on a horizontal surface in a nice sunny
> location. *Start with the higher end of the wedge to the north* and the
> sides aligned on a north-south line and the sharp edge should be on an
> east-west line.
>
> Example 1:
>
> If you have a sundial that was designed for Latitude -20 deg. And relocate
> it at Latitude -50 deg.
>
> Would you start with the higher end of the 30 deg wedge to the North. Or
> would it be to the South?
>
> *
>
> Example 2:
>
> If you have a sundial that was designed for Latitude 50 deg. And relocate
> it at 20 deg.
>
> Would you start with the higher end of the 30 deg wedge to the North. Or
> would it be to the South?
>
> *
>
> Please correct me if I am wrong. I think that both examples would be to
> the South.
>
> Roderick.
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

Steve tells me that the lack of longitude correction instructions was
due to my choice of 'local solar time' as the time indication. When I
use 'UTC-5' I get the instructions.

---

On 2023-04-02 21:30, kool...@dickkoolish.com wrote:

I tried the app. I used 40, -75 and 45, -70. It just said to use a 5 degree wedge and said nothing about a longitude correction. 

I communicated to Steve privately last week. I said that a longitude correction was a rotation around the gnomon. Does anybody else believe this? One of the books, I can't remember which, calls this The Universal Sundial Principle. It says that two dials with the same orientation in space with respect to the sun will read the same time, regardless of where on earth they are. 


---

On 2023-04-02 19:24, Steve Lelievre wrote: 

Jack, 

Try out my calculator! You can specify a time zone meridian for the dial at its original location, or at its new location, or both. If there is an effective longitude change, it'll tell you how to position (twist) the dial on the wedge and how to orient the wedge itself, turning it away (rotating it ) from the meridian line. 

Steve 

On 2023-04-02 3:59 p.m., Jack Aubert wrote: 

I thought about this briefly.  I had always thought that the purpose of the shim or wedge adjustment was to tip the dial north or south so that dial is at the latitude it was originally designed for.  If the original dial has a built-in longitude correction, that could also be factored into a wedge which would have both a north-south and east-west axis.  But a wedge would not work if it moved the gnomon out of alignment with the with the rotation of the earth (or the celestial sphere).  I think a longitudinal adjustment would only work if he original dial had a time-zone offset included by rotating the hour lines with respect to the origin of the gnomon.  

Does this make sense?  It sounds like a good project for a 3-D printer.

Jack 


From: sundial  On Behalf Of Steve Lelievre
Sent: Sunday, April 2, 2023 5:16 PM
To: Michael Ossipoff 
Cc: Sundial List 
Subject: Re: Adjusting dial to new location 

Michael, 

Yes, I recognize that to get Mean Time involves Equation of Time adjustment and that Equation of Longitude can be handled there to give Standard Time (or DST). 

But anyway, my inquiry was to seek an online wedge calculator. Nobody identified one and  a week seemed an adequate wait for responses, so I've just written one.  Anyone who's interested, please see 

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude 

Cheers, 

Steve 

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote: 

I just want to mention that the shim under the north or south edge of the dial is only for latitude. Longitude is corrected-for by changing the constant term of the Sundial-Time to Clock-Time conversion. 

But usually Sundial-Time, Local True Solar Time, is what I'd want from a sundial. 

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre  wrote: 


Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?


I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.


Many thanks,

Steve

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


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

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

Re: Adjusting dial to new location

[Rod Wall]

Hi Steve,

For both examples below with all sundials at the same Longitude. The 
instructions indicate:


Place the wedge-sundial assembly on a horizontal surface in a nice sunny 
location. *Start with the higher end of the wedge to the north* and the 
sides aligned on a north-south line and the sharp edge should be on an 
east-west line.


Example 1:

If you have a sundial that was designed for Latitude -20 deg. And 
relocate it at Latitude -50 deg.


Would you start with the higher end of the 30 deg wedge to the North. Or 
would it be to the South?


*

Example 2:

If you have a sundial that was designed for Latitude 50 deg. And 
relocate it at 20 deg.


Would you start with the higher end of the 30 deg wedge to the North. Or 
would it be to the South?


*

Please correct me if I am wrong. I think that both examples would be to 
the South.


Roderick.

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

Re: Adjusting dial to new location

[Michael Ossipoff]

Tipping the dial-plate for latitude makes it exactly as if the dial were at
the latitude it was made for. No need for a 2nd wedge. If the new longitude
differs from the old on, then just adjust your longitude correction
constant. + 4 minutes for every degree more west of your standard meridian.

On Sun, Apr 2, 2023 at 17:20 Rod Wall  wrote:

> Hi Jack and Steve,
>
> To implement what Jack has indicated. You could have two wedges one on top
> of each other. One for Latitude correction and one for Longitude correction.
>
> You could also just use a Longitude correction wedge if you only wanted to
> correct for Longitude.
>
> When writing instructions. Please also include people who live in the
> southern hemisphere, we do also have sundials.
>
> Do I have this correct?
>
> Roderick.
>
> On 3/04/2023 9:24 am, Steve Lelievre wrote:
>
> Jack,
>
> Try out my calculator! You can specify a time zone meridian for the dial
> at its original location, or at its new location, or both. If there is an
> effective longitude change, it'll tell you how to position (twist) the dial
> on the wedge and how to orient the wedge itself, turning it away (rotating
> it ) from the meridian line.
>
> Steve
>
>
> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>
> I thought about this briefly.  I had always thought that the purpose of
> the shim or wedge adjustment was to tip the dial north or south so that
> dial is at the latitude it was originally designed for.  If the original
> dial has a built-in longitude correction, that could also be factored into
> a wedge which would have both a north-south and east-west axis.  But a
> wedge would not work if it moved the gnomon out of alignment with the with
> the rotation of the earth (or the celestial sphere).  I think a
> longitudinal adjustment would only work if he original dial had a time-zone
> offset included by rotating the hour lines with respect to the origin of
> the gnomon.
>
>
>
> Does this make sense?  It sounds like a good project for a 3-D printer.
>
>
>
> Jack
>
>
>
> *From:* sundial 
>  *On Behalf Of *Steve Lelievre
> *Sent:* Sunday, April 2, 2023 5:16 PM
> *To:* Michael Ossipoff  
> *Cc:* Sundial List  
> *Subject:* Re: Adjusting dial to new location
>
>
>
> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
>
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
>
>
> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
> sundial.
>
>
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[koolish]

I tried the app. I used 40, -75 and 45, -70. It just said to use a 5
degree wedge and said nothing about a longitude correction. 


I communicated to Steve privately last week. I said that a longitude
correction was a rotation around the gnomon. Does anybody else believe
this? One of the books, I can't remember which, calls this The Universal
Sundial Principle. It says that two dials with the same orientation in
space with respect to the sun will read the same time, regardless of
where on earth they are. 


---

On 2023-04-02 19:24, Steve Lelievre wrote:

Jack, 

Try out my calculator! You can specify a time zone meridian for the dial at its original location, or at its new location, or both. If there is an effective longitude change, it'll tell you how to position (twist) the dial on the wedge and how to orient the wedge itself, turning it away (rotating it ) from the meridian line. 

Steve 

On 2023-04-02 3:59 p.m., Jack Aubert wrote: 

I thought about this briefly.  I had always thought that the purpose of the shim or wedge adjustment was to tip the dial north or south so that dial is at the latitude it was originally designed for.  If the original dial has a built-in longitude correction, that could also be factored into a wedge which would have both a north-south and east-west axis.  But a wedge would not work if it moved the gnomon out of alignment with the with the rotation of the earth (or the celestial sphere).  I think a longitudinal adjustment would only work if he original dial had a time-zone offset included by rotating the hour lines with respect to the origin of the gnomon.  

Does this make sense?  It sounds like a good project for a 3-D printer.

Jack 


From: sundial  On Behalf Of Steve Lelievre
Sent: Sunday, April 2, 2023 5:16 PM
To: Michael Ossipoff 
Cc: Sundial List 
Subject: Re: Adjusting dial to new location 

Michael, 

Yes, I recognize that to get Mean Time involves Equation of Time adjustment and that Equation of Longitude can be handled there to give Standard Time (or DST). 

But anyway, my inquiry was to seek an online wedge calculator. Nobody identified one and  a week seemed an adequate wait for responses, so I've just written one.  Anyone who's interested, please see 

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude 

Cheers, 

Steve 

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote: 

I just want to mention that the shim under the north or south edge of the dial is only for latitude. Longitude is corrected-for by changing the constant term of the Sundial-Time to Clock-Time conversion. 

But usually Sundial-Time, Local True Solar Time, is what I'd want from a sundial. 

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre  wrote: 


Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?


I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.


Many thanks,

Steve

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


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

Re: Adjusting dial to new location

[Steve Lelievre]

You don’t need two wedges, you just skew the positioning to do both
adjustments in one.

If you have The Compendium vol 7 issue 1, take a look at the articles by
Fred Sawyer and Bill Gottesman.

Steve

On Sun, Apr 2, 2023 at 17:20, Rod Wall  wrote:

> Hi Jack and Steve,
>
> To implement what Jack has indicated. You could have two wedges one on top
> of each other. One for Latitude correction and one for Longitude correction.
>
> You could also just use a Longitude correction wedge if you only wanted to
> correct for Longitude.
>
> When writing instructions. Please also include people who live in the
> southern hemisphere, we do also have sundials.
>
> Do I have this correct?
>
> Roderick.
>
> On 3/04/2023 9:24 am, Steve Lelievre wrote:
>
> Jack,
>
> Try out my calculator! You can specify a time zone meridian for the dial
> at its original location, or at its new location, or both. If there is an
> effective longitude change, it'll tell you how to position (twist) the dial
> on the wedge and how to orient the wedge itself, turning it away (rotating
> it ) from the meridian line.
>
> Steve
>
>
> On 2023-04-02 3:59 p.m., Jack Aubert wrote:
>
> I thought about this briefly.  I had always thought that the purpose of
> the shim or wedge adjustment was to tip the dial north or south so that
> dial is at the latitude it was originally designed for.  If the original
> dial has a built-in longitude correction, that could also be factored into
> a wedge which would have both a north-south and east-west axis.  But a
> wedge would not work if it moved the gnomon out of alignment with the with
> the rotation of the earth (or the celestial sphere).  I think a
> longitudinal adjustment would only work if he original dial had a time-zone
> offset included by rotating the hour lines with respect to the origin of
> the gnomon.
>
>
>
> Does this make sense?  It sounds like a good project for a 3-D printer.
>
>
>
> Jack
>
>
>
> *From:* sundial 
>  *On Behalf Of *Steve Lelievre
> *Sent:* Sunday, April 2, 2023 5:16 PM
> *To:* Michael Ossipoff  
> *Cc:* Sundial List  
> *Subject:* Re: Adjusting dial to new location
>
>
>
> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
>
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
>
>
> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
> sundial.
>
>
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
> ---https://lists.uni-koeln.de/mailman/listinfo/sundial
>
> --
Cell +1 778 837 5771
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Re: Adjusting dial to new location

[Rod Wall]

Hi Jack and Steve,

To implement what Jack has indicated. You could have two wedges one on 
top of each other. One for Latitude correction and one for Longitude 
correction.


You could also just use a Longitude correction wedge if you only wanted 
to correct for Longitude.


When writing instructions. Please also include people who live in the 
southern hemisphere, we do also have sundials.


Do I have this correct?

Roderick.

On 3/04/2023 9:24 am, Steve Lelievre wrote:


Jack,

Try out my calculator! You can specify a time zone meridian for the 
dial at its original location, or at its new location, or both. If 
there is an effective longitude change, it'll tell you how to position 
(twist) the dial on the wedge and how to orient the wedge itself, 
turning it away (rotating it ) from the meridian line.


Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:


I thought about this briefly.  I had always thought that the purpose 
of the shim or wedge adjustment was to tip the dial north or south so 
that dial is at the latitude it was originally designed for.  If the 
original dial has a built-in longitude correction, that could also be 
factored into a wedge which would have both a north-south and 
east-west axis.  But a wedge would not work if it moved the gnomon 
out of alignment with the with the rotation of the earth (or the 
celestial sphere).  I think a longitudinal adjustment would only work 
if he original dial had a time-zone offset included by rotating the 
hour lines with respect to the origin of the gnomon.


Does this make sense?  It sounds like a good project for a 3-D printer.

Jack

*From:* sundial  *On Behalf Of *Steve 
Lelievre

*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff 
*Cc:* Sundial List 
*Subject:* Re: Adjusting dial to new location

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time 
adjustment and that Equation of Longitude can be handled there to 
give Standard Time (or DST).


But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so 
I've just written one. Anyone who's interested, please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south
edge of the dial is only for latitude. Longitude is corrected-for
by changing the constant term of the Sundial-Time to Clock-Time
conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d want
from a sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre
 wrote:

Hi,

Can anyone point me to an existing online calculator for
making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the
calculation; I just
want to be able to point people to a calculator that has
already been
proved on the internet. It should use the original location
(latitude
and longitude) and the new location to calculate the angle of
slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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---
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---
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Re: RE: Adjusting dial to new location

[Steve Lelievre]

Jack,

Try out my calculator! You can specify a time zone meridian for the dial 
at its original location, or at its new location, or both. If there is 
an effective longitude change, it'll tell you how to position (twist) 
the dial on the wedge and how to orient the wedge itself, turning it 
away (rotating it ) from the meridian line.


Steve


On 2023-04-02 3:59 p.m., Jack Aubert wrote:


I thought about this briefly.  I had always thought that the purpose 
of the shim or wedge adjustment was to tip the dial north or south so 
that dial is at the latitude it was originally designed for.  If the 
original dial has a built-in longitude correction, that could also be 
factored into a wedge which would have both a north-south and 
east-west axis.  But a wedge would not work if it moved the gnomon out 
of alignment with the with the rotation of the earth (or the celestial 
sphere).  I think a longitudinal adjustment would only work if he 
original dial had a time-zone offset included by rotating the hour 
lines with respect to the origin of the gnomon.


Does this make sense?  It sounds like a good project for a 3-D printer.

Jack

*From:* sundial  *On Behalf Of *Steve 
Lelievre

*Sent:* Sunday, April 2, 2023 5:16 PM
*To:* Michael Ossipoff 
*Cc:* Sundial List 
*Subject:* Re: Adjusting dial to new location

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time 
adjustment and that Equation of Longitude can be handled there to give 
Standard Time (or DST).


But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so 
I've just written one.  Anyone who's interested, please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south edge
of the dial is only for latitude. Longitude is corrected-for by
changing the constant term of the Sundial-Time to Clock-Time
conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d want
from a sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre
 wrote:

Hi,

Can anyone point me to an existing online calculator for
making a wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the
calculation; I just
want to be able to point people to a calculator that has
already been
proved on the internet. It should use the original location
(latitude
and longitude) and the new location to calculate the angle of
slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


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

RE: Adjusting dial to new location

[Jack Aubert via sundial]

Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die
eigentliche Nachricht steht dadurch in einem Anhang.

This message was wrapped to be DMARC compliant. The actual message
text is therefore in an attachment.--- Begin Message ---
I thought about this briefly.  I had always thought that the purpose of the 
shim or wedge adjustment was to tip the dial north or south so that dial is at 
the latitude it was originally designed for.  If the original dial has a 
built-in longitude correction, that could also be factored into a wedge which 
would have both a north-south and east-west axis.  But a wedge would not work 
if it moved the gnomon out of alignment with the with the rotation of the earth 
(or the celestial sphere).  I think a longitudinal adjustment would only work 
if he original dial had a time-zone offset included by rotating the hour lines 
with respect to the origin of the gnomon.  

 

Does this make sense?  It sounds like a good project for a 3-D printer.   

 

Jack

 

From: sundial  On Behalf Of Steve Lelievre
Sent: Sunday, April 2, 2023 5:16 PM
To: Michael Ossipoff 
Cc: Sundial List 
Subject: Re: Adjusting dial to new location

 

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time adjustment and 
that Equation of Longitude can be handled there to give Standard Time (or DST).

But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so I've just 
written one.  Anyone who's interested, please see

https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve

 

On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:

I just want to mention that the shim under the north or south edge of the dial 
is only for latitude. Longitude is corrected-for by changing the constant term 
of the Sundial-Time to Clock-Time conversion.

 

But usually Sundial-Time, Local True Solar Time, is what I’d want from a 
sundial.

 

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre mailto:steve.lelievre.can...@gmail.com> > wrote:

Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.

Many thanks,

Steve


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

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

Re: Adjusting dial to new location

[Michael Ossipoff]

...& thank you for doing so, because online calculators & dial-printing
programs make sundials readily accessible to everyone.

On Sun, Apr 2, 2023 at 5:15 PM Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Michael,
>
> Yes, I recognize that to get Mean Time involves Equation of Time
> adjustment and that Equation of Longitude can be handled there to give
> Standard Time (or DST).
>
> But anyway, my inquiry was to seek an online wedge calculator. Nobody
> identified one and  a week seemed an adequate wait for responses, so I've
> just written one.  Anyone who's interested, please see
>
>
> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude
>
> Cheers,
>
> Steve
>
> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
>
> I just want to mention that the shim under the north or south edge of the
> dial is only for latitude. Longitude is corrected-for by changing the
> constant term of the Sundial-Time to Clock-Time conversion.
>
> But usually Sundial-Time, Local True Solar Time, is what I’d want from a
> sundial.
>
> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
> steve.lelievre.can...@gmail.com> wrote:
>
>> Hi,
>>
>> Can anyone point me to an existing online calculator for making a wedge
>> to adjust a horizontal dial to a new latitude and longitude?
>>
>> I am not asking for an explanation of how to do the calculation; I just
>> want to be able to point people to a calculator that has already been
>> proved on the internet. It should use the original location (latitude
>> and longitude) and the new location to calculate the angle of slope of
>> the wedge and the required rotation from the meridian.
>>
>> Many thanks,
>>
>> Steve
>>
>>
>> ---
>> https://lists.uni-koeln.de/mailman/listinfo/sundial
>>
>>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Re: Adjusting dial to new location

[Steve Lelievre]

Michael,

Yes, I recognize that to get Mean Time involves Equation of Time 
adjustment and that Equation of Longitude can be handled there to give 
Standard Time (or DST).


But anyway, my inquiry was to seek an online wedge calculator. Nobody 
identified one and  a week seemed an adequate wait for responses, so 
I've just written one.  Anyone who's interested, please see


https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude

Cheers,

Steve


On 2023-04-02 1:41 p.m., Michael Ossipoff wrote:
I just want to mention that the shim under the north or south edge of 
the dial is only for latitude. Longitude is corrected-for by changing 
the constant term of the Sundial-Time to Clock-Time conversion.


But usually Sundial-Time, Local True Solar Time, is what I’d want from 
a sundial.


On Sun, Mar 26, 2023 at 14:30 Steve Lelievre 
 wrote:


Hi,

Can anyone point me to an existing online calculator for making a
wedge
to adjust a horizontal dial to a new latitude and longitude?

I am not asking for an explanation of how to do the calculation; I
just
want to be able to point people to a calculator that has already been
proved on the internet. It should use the original location (latitude
and longitude) and the new location to calculate the angle of
slope of
the wedge and the required rotation from the meridian.

Many thanks,

Steve


---
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---
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Re: Adjusting dial to new location

[Michael Ossipoff]

I just want to mention that the shim under the north or south edge of the
dial is only for latitude. Longitude is corrected-for by changing the
constant term of the Sundial-Time to Clock-Time conversion.

But usually Sundial-Time, Local True Solar Time, is what I’d want from a
sundial.

On Sun, Mar 26, 2023 at 14:30 Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

> Hi,
>
> Can anyone point me to an existing online calculator for making a wedge
> to adjust a horizontal dial to a new latitude and longitude?
>
> I am not asking for an explanation of how to do the calculation; I just
> want to be able to point people to a calculator that has already been
> proved on the internet. It should use the original location (latitude
> and longitude) and the new location to calculate the angle of slope of
> the wedge and the required rotation from the meridian.
>
> Many thanks,
>
> Steve
>
>
> ---
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
---
https://lists.uni-koeln.de/mailman/listinfo/sundial

Adjusting dial to new location

[Steve Lelievre]

Hi,

Can anyone point me to an existing online calculator for making a wedge 
to adjust a horizontal dial to a new latitude and longitude?


I am not asking for an explanation of how to do the calculation; I just 
want to be able to point people to a calculator that has already been 
proved on the internet. It should use the original location (latitude 
and longitude) and the new location to calculate the angle of slope of 
the wedge and the required rotation from the meridian.


Many thanks,

Steve


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