RE: Is this sundial business 'genuine', or not?

[Roger]

Hi Rod,

We both have the same concept. I applied it to analemmatic sundials. You 
applied it to equatorial, horizontal and vertical sundials. When I go to NASS 
conferences or talk to groups I generally carry a disc and rod. All sundials 
start with a polar gnomon and equatorial disc.

Roger Bailey
Walking Shadow Designs


From: rodwall1...@gmail.com
Sent: July 17, 2018 4:14 PM
To: Michael Ossipoff; Steve Lelievre
Cc: sundial list
Subject: Re: Is this sundial business 'genuine', or not?

Hi all,

The following is what I think is the best way to describe how sundials work to 
kids or anyone.


1st start with the largest sundial in the world. Planet Earth the Master 
sundial clock. Stick a vertical stick into the ground at the South pole or 
North pole. And describe how the shadow shows the time throughout the day. Draw 
the 24 hour lines every 15 deg and that 15 deg x 24 hours = 360 deg one day.

Then show how the Equatorial sundial relates to our stick sundial at the poles. 
Place it at the South or North pole. And show that the Equatorial sundial style 
edge is parallel with the stick and the axis of the Earth. And that the hour 
lines are the same every 15 deg. And that it will keep the same time.

Then place the Equatorial sundial anywhere on earth. And show that the sundial 
is geared to Earth the largest sundial in the world (the Master sundial clock). 
Therefore it will keep the same time. Show how the sundial time markings relate 
to your local time. And that the style edge of the sundial must be parallel 
with the axis of the earth and parallel with the vertical stick at the poles. 
And that at night time the sundial is in the shadow of Earth.

Then place a horizontal sundial at the same location. And describe that the 
style edge is also placed parallel with the stick and the axis of the Earth. 
And how the hour lines are projected every 15 deg from the horizontal sundial 
style. That is to place the style edge of the equatorial sundial onto the 
horizontal sundial style edge and use it to project the hour points onto the 
horizontal base of the horizontal sundial. Then draw the hour lines on the 
horizontal sundial. Then show the direction the horizontal sundial faces if in 
the Southern hemisphere or Northern hemisphere. To ensure that the Style edge 
is parallel with the axis of the Earth and stick.

Then go through the same process as you did for the horizontal sundial but with 
a vertical sundial on a wall. And show that it must face North towards the sun 
if in the southern hemisphere and face South for the northern hemisphere. Yes I 
live in sunny Australia in the southern hemisphere.

Then show how the angle of the style edge relates to the latitude of the 
location of the sundial. To make the style edge parallel with the stick and 
axis of the Earth.

Depending on how far you want to go. Describe how a horizontal sundial that is 
not designed for the  latitude of the location you are at. Can be corrected if 
a block is placed under the dial to make the style edge parallel with the axis 
of the Earth and the stick.

Describe how longitude relates to your location. And that the longitude time 
zones are every 15 deg. 15 deg x 24 hours = 360 deg one day.

One way to describe the above is to use a globe of the world or a large beach 
ball. With cardboard cutouts for sundials. And a lamp (sun) to make the 
shadows. Young kids and some adults learn better when learning in the sand pit 
(concrete learning) rather that just using symbolic words (symbolic learning).

That is how I explain it.

If anyone wants to publish the above. Please do and let them know where it came 
from.

Have fun,

Roderick Wall
Sunny Australia.



---
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RE: Is this sundial business 'genuine', or not?

[Roger]

Hi Jack and Michael,

I don’t agree. The concept is very simple. Perhaps you have had bad teachers. 
One of my presentations at the upcoming conference is a purely grapghical 
method of designing an analemmatic sundial. No trig, not even geometry other 
than the Greek’s ruler and string or a simple math set with ruler, protractor 
and a compass.  From this graphical technique comes a whole new concept by  
Chris Lusby Taylor for seasonal makers that I will describe at the conference 
next month.

To demonstrate the simple concepts for analemmatic sundials, start with this 
experiment as a class activity, hands on and interactive. Cut out a circle of 
cardboard. Stick a pencil through the center at a right angle to the disc. Hold 
it with the pencil vertical. Look straight down on the disc, a circle true 
size. Hour angles drawn every 15° would also be true angles. The pencil is seen 
as a point. Now physically drop the disc and pencil onto a horizontal table. 
Get down to view across the table and turn the disc to see it on edge. It will 
be seen as a true length straight line equal to the diameter of the circle. The 
pencil will also be seen a true length line. If you chose the right length of 
pencil, the pencil will make an angle to the horizontal equal to your latitude. 
The disc will make an angle to the co-latitude.  Now get up and look straight 
down on the disc and pencil on the table. The disc will be seen as an ellipse 
and the pencil as a shorter line as neither disc or pencil are true length. 
Look at it straight down from above and mark the point on the desk that is 
directly under the end of the hour mark on the disk starting with the disc 
turned to the starting point noon being directly under the pencil. These points 
define. the hour ellipse for an analemmatic sundial.

Next the enigmatic date line. Consider the sun shining down at noon at any day 
of the year onto the pencil through the disc on the table. The sun shines down 
on the pencil and there is a unique point on the pencil each day where the sun 
at noon shines directly onto the rim of the disc. At the summer solstice the 
sun is high in the sky. The angle of the suns ray down to the disc rim is at an 
angle of 23.5° to the disc. At the winter solstice the angle is -23.5 ° On the 
spring and fall equinox the angle is 0°. Every day has a different angle, the 
solar declination for that day. Now you could switch to ruler and protractor 
marking on paper right angle  triangles with the base equal to the disc radius. 
Measure angles from the base point up at the chosen declination angle and draw 
a line at that angle to the line at right angles to the other end of the base 
line for the declination points for the chosen dates. Now draw a line for the 
horizon at an angle to the disc base line equal the latitude. Draw lines 
perpendicular to the horizon line to the chosen declination date points.  The 
points on the horizon line are the points where you stand on the analemmatic 
sundial. 

In one class activity session all the kids with a good teacher could make their 
own analemmatic sundial based on these simple concepts. It involves simple 
tools  from the standard geometry set and a simple concept of looking at a 
circular disc with a rod through the center from different points of view.

The general problem is that sundials are not on the curriculum for any school 
boards. Teachers teach to the curriculum. The few teachers I have met in NASS 
are excellent but there are very few others are interested in such an 
extracurricular activity. Perhaps that is the value of a analemmatic sundial 
installation at a school would be to stimulate interest.

Regards, Roger Bailey
Walking Shadow Designs

From: Jack Aubert
Sent: July 17, 2018 6:27 AM
To: 'Michael Ossipoff'; 'sundial list'
Subject: RE: Is this sundial business 'genuine', or not?

I very much agree with this.  In fact, at the risk of sounding stupid, I have 
to confess that I don’t have an intuitive grasp of how an analemmatic dial 
works.  Yes, I have at various times gone through the explanation, but it does 
not stick in any way that I can mentally attach to the plane of the earth’s 
surface and the motion of the celestial sphere.  I know I could review the 
geometry and remember it if I tried but agree that the geometrical projections 
involved are beyond the grasp of almost all children and almost all adults.     
 

Jack

From: sundial  On Behalf Of Michael Ossipoff
Sent: Tuesday, July 17, 2018 12:29 AM
To: sundial list 
Subject: Re: Is this sundial business 'genuine', or not?


To continue something that I started before:

The derivation of the construction of the Analemmatic could be explained to 
anyone, with 3 lesson-sessions, over 3 days.

Yes, an Analemmatic Dial could be educational, when it gives people incentive 
to study, read about or listen to the dial's derivation, is 
construction-explanation.

So the Analemmatic with its trigonometry requirement, could be 

Re: Is this sundial business 'genuine', or not?

[rodwall1...@gmail.com]

Hi all,
The following is what I think is the best way to describe how sundials work to 
kids or anyone.


1st start with the largest sundial in the world. Planet Earth the Master 
sundial clock. Stick a vertical stick into the ground at the South pole or 
North pole. And describe how the shadow shows the time throughout the day. Draw 
the 24 hour lines every 15 deg and that 15 deg x 24 hours = 360 deg one day.

Then show how the Equatorial sundial relates to our stick sundial at the poles. 
Place it at the South or North pole. And show that the Equatorial sundial style 
edge is parallel with the stick and the axis of the Earth. And that the hour 
lines are the same every 15 deg. And that it will keep the same time.

Then place the Equatorial sundial anywhere on earth. And show that the sundial 
is geared to Earth the largest sundial in the world (the Master sundial clock). 
Therefore it will keep the same time. Show how the sundial time markings relate 
to your local time. And that the style edge of the sundial must be parallel 
with the axis of the earth and parallel with the vertical stick at the poles. 
And that at night time the sundial is in the shadow of Earth.

Then place a horizontal sundial at the same location. And describe that the 
style edge is also placed parallel with the stick and the axis of the Earth. 
And how the hour lines are projected every 15 deg from the horizontal sundial 
style. That is to place the style edge of the equatorial sundial onto the 
horizontal sundial style edge and use it to project the hour points onto the 
horizontal base of the horizontal sundial. Then draw the hour lines on the 
horizontal sundial. Then show the direction the horizontal sundial faces if in 
the Southern hemisphere or Northern hemisphere. To ensure that the Style edge 
is parallel with the axis of the Earth and stick.

Then go through the same process as you did for the horizontal sundial but with 
a vertical sundial on a wall. And show that it must face North towards the sun 
if in the southern hemisphere and face South for the northern hemisphere. Yes I 
live in sunny Australia in the southern hemisphere.

Then show how the angle of the style edge relates to the latitude of the 
location of the sundial. To make the style edge parallel with the stick and 
axis of the Earth.

Depending on how far you want to go. Describe how a horizontal sundial that is 
not designed for the  latitude of the location you are at. Can be corrected if 
a block is placed under the dial to make the style edge parallel with the axis 
of the Earth and the stick.

Describe how longitude relates to your location. And that the longitude time 
zones are every 15 deg. 15 deg x 24 hours = 360 deg one day.

One way to describe the above is to use a globe of the world or a large beach 
ball. With cardboard cutouts for sundials. And a lamp (sun) to make the 
shadows. Young kids and some adults learn better when learning in the sand pit 
(concrete learning) rather that just using symbolic words (symbolic learning).

That is how I explain it.

If anyone wants to publish the above. Please do and let them know where it came 
from.

Have fun,

Roderick Wall
Sunny Australia.

---
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RE: Is this sundial business 'genuine', or not?

[Astrovisuals]

  and of course a south windowill 
is the one that gets sunlight all year.




One other disadvantage is that, with only an aperature at the top, it won't 
show times before 6 a.m. or after 6 p.,.




That's easily remedied  by having additional aperatures at the 6 am & pm 
positions, with a few separate special hour-lines for use with those 
aperatures.  I'd make those 6-o'clock aperatures double, to make them 
easily-distinguished.




For an outdoor use, it could use a big metal drum, or any ready-made 
cylinder, with a hold drilled in it at the top (...and preferably a pair of 
auxilliary 6 o'clock aperatures at each 6 o'clock position, with 
corresponding speial extra hour-lines opposite them.




Michael Ossipoff









On Wed, Jul 11, 2018 at 5:06 AM, William Irvine 
mailto:william.irv...@fastmessage.co.uk> 
> wrote:



Thanks to the people who responded, either direct to this Mailing
List - or had E-mailed to me privately, with their own comments.

Based on those replies, I contacted "Sunclocks" to ask why their
price was so low (compared with the people acting as Distributors
for them) - as well as why they show so many 'negative' details
on their website, telling people about dangers of Human Sundials.


I will not give away the 'secret' here, (as you can always contact
them yourselves if you want) - but it appears that they exploit a
'loophole' in Scottish Law, which allows them to make much greater
profits by persuading customers NOT to purchase, but seemingly it
only works if their advertised price does not go above 20 Pounds.

Apparently, that is why their website says that the price will be
permanently FIXED at this level - and would never be increased at
any time in the future, no matter what happens to 'inflation'.

Doug Hunt explained their overseas Distributors get customized
Plans at the same low cost, and choose their own selling prices
to suit 'local markets' - while "Sunclocks" profit from persons
who do NOT buy, so this is a "win-win" situation for everybody.


Because each "Sunclock" layout will automatically become its own
'advert' (particularly those in public locations), the business
is basically guaranteed a 'chain reaction' of enquiries - plus
they make money regardless of whether any person buys, or not!

After looking at hundereds of pictures on their website (as they
say themselves "from Australia to Alaska and Tasmania to Tibet"),
I now understand why it is such a world-wide success - and they
do not even need to supply a 'physical' product, since all sets
of customized Plans are simply 'down-loaded' via their website.

However, as Frank King indicated in his reply, some unscrupulous
people try 're-selling' those Plans (or even making counterfeit
copies, under their own name) - but that just annoys people who
buy them, as the 'Latitude & Longitude' will be wrong so all the
measurements plus layout instructions would not apply either.


Many thanks, also, to those people who gave me suggestions about
various means of making an income from sundials - for example by
giving some 'lectures', as I prefer not to work in stone/metal.

As far as my own 'paying hobby' is concerned, I might just try
painting some "Sunclocks" on school playgrounds - because other
businesses already do it, making hundreds of Pounds each time!



Sincerely,

Bill Irvine.


--

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Message: 2
Date: Tue, 17 Jul 2018 12:42:29 -0400
From: Michael Ossipoff 
To: Jack Aubert 
Cc: sundial list 
Subject: Re: Is this sundial business 'genuine', or not?
Message-ID:

Content-Type: text/plain; charset="utf-8"

Jack--

And it seems to me that it wouldn't be satisfying, having and using a
sundial, without a complete explanation of its construction-derivation.

You wouldn't have any trouble with the explanation. It's just that it's a
bit long.

I suggest 3 separate discussions, preferably on subsequent days:

1. The Equatorial and Horizontal spherical co-ordinate-systems.

2. The definitions of the sine, cosine and tangent

3. The application of #2 to #1, for determining the Sun's azimuth.

That azimuth formula that that leads to directly gives the Analemmatic
Dial's layout.

Let me just send this post now, and then (maybe this morning, probably this
afternoon, but maybe Wednesday morning) start saying something about topic
#1, above.

Michael Ossipoff



On Tue, Jul 17, 2018 at 9:23 AM, Jack Aubert  wrote:


I very much agree with this.  In fact, at the risk of sounding stupid, I
have to confess that I don?t have an intuitive grasp of how an analemmatic
dial works.  Yes, I have at various times gone

Re: Is this sundial business 'genuine', or not?

[Steve Lelievre]

Sure, any type of dial is fine if it works for the situation.

And apologies to all for the typos in my last message. I think my PC had 
auto-obfuscate turned on.


Steve

On 2018-07-17 11:07 AM, Michael Ossipoff wrote:
Insisting on limiting it to central-gnomon Equatorials sounds unfair to 
students motivated to look at other dials.



---
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Re: Is this sundial business 'genuine', or not?

[Michael Ossipoff]

I'd said:

I suggest 3 separate discussions, preferably on subsequent days:

1. The Equatorial and Horizontal spherical co-ordinate-systems.

2. The definitions of the sine, cosine and tangent

3. The application of #2 to #1, for determining the Sun's azimuth.

That azimuth formula that that leads to directly gives the Analemmatic
Dial's layout.



For the general Reclining-Declining Flat Dial, it could be 5-day series of
discussions::

1. The Equatorial and Horizontal spherical co-ordinate-systems.

2. The definitions of the sine, cosine and tangent

3. The application of #2 to #1, for determining the Sun's altitude and
azimuth, from its h and dec.

4. The generalization of #3 to any two co-ordinate systems.

5. The application of #4 to the Reclining-Declining Dial.

---

We've discussed, here, how the Regiomontanus' construction is derived from
the formula for Solar altitude.

(The Regiomontanus is a portable universal card-altitude dial.)

The Marke Dial is another portable universal card-altitude dial whose
construction is also derived from the altitude formula.

--

It occurs to me that the explanation for the Analemmatic is available in
various sources, and so there probably isn't reason to take up space here
by posting it, unless there are one or more particular requests for it.

--

Michael Ossipoff









On Tue, Jul 17, 2018 at 12:42 PM, Michael Ossipoff 
wrote:

>
> Jack--
>
> And it seems to me that it wouldn't be satisfying, having and using a
> sundial, without a complete explanation of its construction-derivation.
>
> You wouldn't have any trouble with the explanation. It's just that it's a
> bit long.
>
> I suggest 3 separate discussions, preferably on subsequent days:
>
> 1. The Equatorial and Horizontal spherical co-ordinate-systems.
>
> 2. The definitions of the sine, cosine and tangent
>
> 3. The application of #2 to #1, for determining the Sun's azimuth.
>
> That azimuth formula that that leads to directly gives the Analemmatic
> Dial's layout.
>
> Let me just send this post now, and then (maybe this morning, probably
> this afternoon, but maybe Wednesday morning) start saying something about
> topic #1, above.
>
> Michael Ossipoff
>
>
>
> On Tue, Jul 17, 2018 at 9:23 AM, Jack Aubert  wrote:
>
>> I very much agree with this.  In fact, at the risk of sounding stupid, I
>> have to confess that I don’t have an intuitive grasp of how an analemmatic
>> dial works.  Yes, I have at various times gone through the explanation, but
>> it does not stick in any way that I can mentally attach to the plane of the
>> earth’s surface and the motion of the celestial sphere.  I know I could
>> review the geometry and remember it if I tried but agree that the
>> geometrical projections involved are beyond the grasp of almost all
>> children and almost all adults.
>>
>>
>>
>> Jack
>>
>>
>>
>> *From:* sundial  *On Behalf Of *Michael
>> Ossipoff
>> *Sent:* Tuesday, July 17, 2018 12:29 AM
>> *To:* sundial list 
>> *Subject:* Re: Is this sundial business 'genuine', or not?
>>
>>
>>
>>
>>
>> To continue something that I started before:
>>
>>
>>
>> The derivation of the construction of the Analemmatic could be explained
>> to anyone, with 3 lesson-sessions, over 3 days.
>>
>>
>>
>> Yes, an Analemmatic Dial could be educational, when it gives people
>> incentive to study, read about or listen to the dial's derivation, is
>> construction-explanation.
>>
>>
>>
>> So the Analemmatic with its trigonometry requirement, could be useful,
>> helpful, educational, at a highschool (secondary school), college or
>> university.
>>
>>
>>
>> ...but not at an elementary-school (primary school), okay? How many
>> elementary-school kids would want to listen to that explanation?
>>
>>
>>
>> Will someone tell me how an Analemmatic Dial would be educational at an
>> elementary-school?
>>
>>
>>
>> There was a line in the movie "Fatal Attraction", in which the mother is
>> considering taking their primary-school child with her, when she goes to
>> visit her father (probably for the purpose of looking at a nearby house
>> that they're considering purchasing).  The Father questions whether the
>> child should miss school by going on the visit. The mother replies, "What's
>> she going to miss, trigonometry?"
>>
>>
>>
>> What dial's explanation would be of interest to an elementary-school
>> audience?  Any of the Central-Gnomon Equatorial dials, such as the
>> Disk-Equatorial, Band-Equatorial and Cylinder-Equatorial (with central
>> gnomon). Their showing of Solar Time is completely direct.
>>
>>
>>
>> The Horizontal Dial's explanation is brief, and might very well be
>> acceptable, of interest, to many elementary-school students,.
>>
>>
>>
>> Vertical or Reclining, but non-Declining, Flat Dials might not be
>> significantly more difficult to explain, since they're just horizontal
>> dials for a different latitude.   ...demonstrable with a globe.
>>
>>
>>
>> So, if some of the kids are 

Re: Is this sundial business 'genuine', or not?

[Michael Ossipoff]

Steve--

Alright, acknowledged.  But, even so, why not instead have a class design
and build a dial whose construction-derivation would be of interest to
them.   ...or even build, or have it built, for them.

...such as any central-gnomon Equatorial, or any Flat Dial that's
Horizontal, Vertical or Reclining, but not Decllining.   ... (a broad
category that includes the Disk-Equatorial and Polar Dials).

But I do feel that there's nothing wrong with a dial that gives incentive
and encouragement to look at the derivation of the construction of dials
other than the central-gnomon Equatorials.

Insisting on limiting it to central-gnomon Equatorials sounds unfair to
students motivated to look at other dials.

Michael Ossipoff

On Tue, Jul 17, 2018 at 1:50 PM, Steve Lelievre <
steve.lelievre.can...@gmail.com> wrote:

>
> An analemmatic dial is more considered more interesting than other kinds
> because it is somewhat interactive, but I agree that it is a little harder
> to understand. To me though, installing a sundial at a school isn't just
> about, or even primarily about, the teaching of the mechanics of how it
> operates.
>
> The dial will be there for many years and seen my the whole school, not
> just the class that installs it. Its mere presence provides a point of
> interest in the schoolyard, and seeing it may well be the first time a
> child becomes aware that time can be shown by anything other than a clock
> or, more likely these days, the digital display on a microwave oven, TV
> set-top box or a cellphone.
>
> For the class  that does the project, the laying out the dial can
> interesting and educational in itself - practicing how to measure with a
> rule, using angles, and so on. Deciding how to decorate the dial might be a
> cue for discussions about artistic composition and how to choose colours
> that work well together. Perhaps there will be a review of the school motto
> and the virtues it reflects. If the dial is made with a garden, there are
> lessons to be learned about sowing and tending plants. There's basic
> astronomy too - the opportunity for general discussion of the relative
> motion of Earth and Sun, how Earth's rotation causes night and day, and how
> seasons happen.
>
> Trig? Projections? Some students will appreciate detailed discussion, but
> I reckon for most a quick non-technical review of the principles of the
> dial is enough.
>
> Steve
>
>
>  On 2018-07-17 9:42 AM, Michael Ossipoff wrote:
>
>
> Jack--
>
> And it seems to me that it wouldn't be satisfying, having and using a
> sundial, without a complete explanation of its construction-derivation.
>
> You wouldn't have any trouble with the explanation. It's just that it's a
> bit long.
>
> I suggest 3 separate discussions, preferably on subsequent days:
>
> 1. The Equatorial and Horizontal spherical co-ordinate-systems.
>
> 2. The definitions of the sine, cosine and tangent
>
> 3. The application of #2 to #1, for determining the Sun's azimuth.
>
> That azimuth formula that that leads to directly gives the Analemmatic
> Dial's layout.
>
> Let me just send this post now, and then (maybe this morning, probably
> this afternoon, but maybe Wednesday morning) start saying something about
> topic #1, above.
>
> Michael Ossipoff
>
>
>
> On Tue, Jul 17, 2018 at 9:23 AM, Jack Aubert  wrote:
>
>> I very much agree with this.  In fact, at the risk of sounding stupid, I
>> have to confess that I don’t have an intuitive grasp of how an analemmatic
>> dial works.  Yes, I have at various times gone through the explanation, but
>> it does not stick in any way that I can mentally attach to the plane of the
>> earth’s surface and the motion of the celestial sphere.  I know I could
>> review the geometry and remember it if I tried but agree that the
>> geometrical projections involved are beyond the grasp of almost all
>> children and almost all adults.
>>
>>
>>
>> Jack
>>
>>
>>
>
>
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Re: Is this sundial business 'genuine', or not?

[Steve Lelievre]

An analemmatic dial is more considered more interesting than other kinds 
because it is somewhat interactive, but I agree that it is a little 
harder to understand. To me though, installing a sundial at a school 
isn't just about, or even primarily about, the teaching of the mechanics 
of how it operates.


The dial will be there for many years and seen my the whole school, not 
just the class that installs it. Its mere presence provides a point of 
interest in the schoolyard, and seeing it may well be the first time a 
child becomes aware that time can be shown by anything other than a 
clock or, more likely these days, the digital display on a microwave 
oven, TV set-top box or a cellphone.


For the class  that does the project, the laying out the dial can 
interesting and educational in itself - practicing how to measure with a 
rule, using angles, and so on. Deciding how to decorate the dial might 
be a cue for discussions about artistic composition and how to choose 
colours that work well together. Perhaps there will be a review of the 
school motto and the virtues it reflects. If the dial is made with a 
garden, there are lessons to be learned about sowing and tending plants. 
There's basic astronomy too - the opportunity for general discussion of 
the relative motion of Earth and Sun, how Earth's rotation causes night 
and day, and how seasons happen.


Trig? Projections? Some students will appreciate detailed discussion, 
but I reckon for most a quick non-technical review of the principles of 
the dial is enough.


Steve


 On 2018-07-17 9:42 AM, Michael Ossipoff wrote:


Jack--

And it seems to me that it wouldn't be satisfying, having and using a 
sundial, without a complete explanation of its construction-derivation.


You wouldn't have any trouble with the explanation. It's just that 
it's a bit long.


I suggest 3 separate discussions, preferably on subsequent days:

1. The Equatorial and Horizontal spherical co-ordinate-systems.

2. The definitions of the sine, cosine and tangent

3. The application of #2 to #1, for determining the Sun's azimuth.

That azimuth formula that that leads to directly gives the Analemmatic 
Dial's layout.


Let me just send this post now, and then (maybe this morning, probably 
this afternoon, but maybe Wednesday morning) start saying something 
about topic #1, above.


Michael Ossipoff



On Tue, Jul 17, 2018 at 9:23 AM, Jack Aubert > wrote:


I very much agree with this.  In fact, at the risk of sounding
stupid, I have to confess that I don’t have an intuitive grasp of
how an analemmatic dial works.  Yes, I have at various times gone
through the explanation, but it does not stick in any way that I
can mentally attach to the plane of the earth’s surface and the
motion of the celestial sphere.  I know I could review the
geometry and remember it if I tried but agree that the geometrical
projections involved are beyond the grasp of almost all children
and almost all adults.

Jack



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Frank W. Cousins

[Dan-George Uza]

Not realy a biography, but rather an investigation into the life and work
of Frank W. Cousins - author of "Sundials - The Art and Science of
Gnomonics / A Simplified Approach by Means of the Equatorial Dial". Text is
German, but I guess Google Translate works well enough.

https://scilogs.spektrum.de/relativ-einfach/frank-w-cousins-amateurastronom-ingenieur-buchbesitzer/

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

Re: Is this sundial business 'genuine', or not?

[Michael Ossipoff]

Jack--

And it seems to me that it wouldn't be satisfying, having and using a
sundial, without a complete explanation of its construction-derivation.

You wouldn't have any trouble with the explanation. It's just that it's a
bit long.

I suggest 3 separate discussions, preferably on subsequent days:

1. The Equatorial and Horizontal spherical co-ordinate-systems.

2. The definitions of the sine, cosine and tangent

3. The application of #2 to #1, for determining the Sun's azimuth.

That azimuth formula that that leads to directly gives the Analemmatic
Dial's layout.

Let me just send this post now, and then (maybe this morning, probably this
afternoon, but maybe Wednesday morning) start saying something about topic
#1, above.

Michael Ossipoff



On Tue, Jul 17, 2018 at 9:23 AM, Jack Aubert  wrote:

> I very much agree with this.  In fact, at the risk of sounding stupid, I
> have to confess that I don’t have an intuitive grasp of how an analemmatic
> dial works.  Yes, I have at various times gone through the explanation, but
> it does not stick in any way that I can mentally attach to the plane of the
> earth’s surface and the motion of the celestial sphere.  I know I could
> review the geometry and remember it if I tried but agree that the
> geometrical projections involved are beyond the grasp of almost all
> children and almost all adults.
>
>
>
> Jack
>
>
>
> *From:* sundial  *On Behalf Of *Michael
> Ossipoff
> *Sent:* Tuesday, July 17, 2018 12:29 AM
> *To:* sundial list 
> *Subject:* Re: Is this sundial business 'genuine', or not?
>
>
>
>
>
> To continue something that I started before:
>
>
>
> The derivation of the construction of the Analemmatic could be explained
> to anyone, with 3 lesson-sessions, over 3 days.
>
>
>
> Yes, an Analemmatic Dial could be educational, when it gives people
> incentive to study, read about or listen to the dial's derivation, is
> construction-explanation.
>
>
>
> So the Analemmatic with its trigonometry requirement, could be useful,
> helpful, educational, at a highschool (secondary school), college or
> university.
>
>
>
> ...but not at an elementary-school (primary school), okay? How many
> elementary-school kids would want to listen to that explanation?
>
>
>
> Will someone tell me how an Analemmatic Dial would be educational at an
> elementary-school?
>
>
>
> There was a line in the movie "Fatal Attraction", in which the mother is
> considering taking their primary-school child with her, when she goes to
> visit her father (probably for the purpose of looking at a nearby house
> that they're considering purchasing).  The Father questions whether the
> child should miss school by going on the visit. The mother replies, "What's
> she going to miss, trigonometry?"
>
>
>
> What dial's explanation would be of interest to an elementary-school
> audience?  Any of the Central-Gnomon Equatorial dials, such as the
> Disk-Equatorial, Band-Equatorial and Cylinder-Equatorial (with central
> gnomon). Their showing of Solar Time is completely direct.
>
>
>
> The Horizontal Dial's explanation is brief, and might very well be
> acceptable, of interest, to many elementary-school students,.
>
>
>
> Vertical or Reclining, but non-Declining, Flat Dials might not be
> significantly more difficult to explain, since they're just horizontal
> dials for a different latitude.   ...demonstrable with a globe.
>
>
>
> So, if some of the kids are little vandals, you could install a South
> Vertical Dial, bracket-mounted high on a wall (or flat-mounted on a
> south-wall).
>
>
>
> The Circumference-Aperture Cylindrical Equatorial Dial would be easier to
> explain than the Analemmatic, but its explanation might still only be of
> interest to highschool students.
>
>
>
> ...because of its geometric diagram, with its triangles, with
> letter-labeled angles, and the equations relating its angles--and the
> making of new equations by doing the same thing to both sides of an
> equation, or adding or subtracting two equations, or substituting one equal
> thing for another in an equation--sounds like a secondary-school topic.
>
>
>
> Well, probably pre-secondary school (junior-high, middle-school) kids too,
> because when I was in junior-high, our general-math class introduced
> equation-solving.
>
>
>
> ...but I don't know if there would be much interest in it in
> primary-school. I don't know if I'd be brave enough to get up in front of a
> class and start explaining it there.
>
>
>
> Anyway, so I'm just saying, only offer dials whose construction derivation
> explanation would be of interest to the people to whom you're offering the
> dial.
>
>
>
> By the way, I say the same thing about map-projections. For a first
> world-map projection, for a wall or a book-page, in primary-school, I
> suggest  Apianus II, an elliptical pseudocylindrical map with equidistant
> parallels.
>
>
>
> (A pseudocylindrical map has parallels that are mutually-parallel straight
> lines, each one uniformly divided by the 

RE: Is this sundial business 'genuine', or not?

[Jack Aubert]

I very much agree with this.  In fact, at the risk of sounding stupid, I have 
to confess that I don’t have an intuitive grasp of how an analemmatic dial 
works.  Yes, I have at various times gone through the explanation, but it does 
not stick in any way that I can mentally attach to the plane of the earth’s 
surface and the motion of the celestial sphere.  I know I could review the 
geometry and remember it if I tried but agree that the geometrical projections 
involved are beyond the grasp of almost all children and almost all adults. 
 

 

Jack

 

From: sundial  On Behalf Of Michael Ossipoff
Sent: Tuesday, July 17, 2018 12:29 AM
To: sundial list 
Subject: Re: Is this sundial business 'genuine', or not?

 

 

To continue something that I started before:

 

The derivation of the construction of the Analemmatic could be explained to 
anyone, with 3 lesson-sessions, over 3 days.

 

Yes, an Analemmatic Dial could be educational, when it gives people incentive 
to study, read about or listen to the dial's derivation, is 
construction-explanation.

 

So the Analemmatic with its trigonometry requirement, could be useful, helpful, 
educational, at a highschool (secondary school), college or university.

 

...but not at an elementary-school (primary school), okay? How many 
elementary-school kids would want to listen to that explanation?

 

Will someone tell me how an Analemmatic Dial would be educational at an 
elementary-school?

 

There was a line in the movie "Fatal Attraction", in which the mother is 
considering taking their primary-school child with her, when she goes to visit 
her father (probably for the purpose of looking at a nearby house that they're 
considering purchasing).  The Father questions whether the child should miss 
school by going on the visit. The mother replies, "What's she going to miss, 
trigonometry?"

 

What dial's explanation would be of interest to an elementary-school audience?  
Any of the Central-Gnomon Equatorial dials, such as the Disk-Equatorial, 
Band-Equatorial and Cylinder-Equatorial (with central gnomon). Their showing of 
Solar Time is completely direct.

 

The Horizontal Dial's explanation is brief, and might very well be acceptable, 
of interest, to many elementary-school students,. 

 

Vertical or Reclining, but non-Declining, Flat Dials might not be significantly 
more difficult to explain, since they're just horizontal dials for a different 
latitude.   ...demonstrable with a globe.

 

So, if some of the kids are little vandals, you could install a South Vertical 
Dial, bracket-mounted high on a wall (or flat-mounted on a south-wall).

 

The Circumference-Aperture Cylindrical Equatorial Dial would be easier to 
explain than the Analemmatic, but its explanation might still only be of 
interest to highschool students.

 

...because of its geometric diagram, with its triangles, with letter-labeled 
angles, and the equations relating its angles--and the making of new equations 
by doing the same thing to both sides of an equation, or adding or subtracting 
two equations, or substituting one equal thing for another in an 
equation--sounds like a secondary-school topic.

 

Well, probably pre-secondary school (junior-high, middle-school) kids too, 
because when I was in junior-high, our general-math class introduced 
equation-solving.

 

...but I don't know if there would be much interest in it in primary-school. I 
don't know if I'd be brave enough to get up in front of a class and start 
explaining it there.

 

Anyway, so I'm just saying, only offer dials whose construction derivation 
explanation would be of interest to the people to whom you're offering the 
dial. 

 

By the way, I say the same thing about map-projections. For a first world-map 
projection, for a wall or a book-page, in primary-school, I suggest  Apianus 
II, an elliptical pseudocylindrical map with equidistant parallels. 

 

(A pseudocylindrical map has parallels that are mutually-parallel straight 
lines, each one uniformly divided by the meridians (In other words, the scale 
along each parallel is uniform.) ).

 

The equator and central meridian have the same scale, and the map is twice as 
wide as high.

 

If that scale along the parallels is the same along each parallel, and is the 
same as the uniform scale along the central meridian, that's the Sinusoidal 
Projection. It's useful, but many people feel that it looks awful.  It's that 
roughly diamond-shaped world map that you might have seen. Apianus II has a 
pleasing globe-similar elliptical shape.

 

Michael Ossipoff

 

 

 

 

 

 

On Thu, Jul 12, 2018 at 8:47 PM, Michael Ossipoff mailto:email9648...@gmail.com> > wrote:

If I may correct a small error in something that I said:

 

I said:

 

 

That's easily remedied  by having additional apertures at the 6 am & pm 
positions, with a few separate special hour-lines for use with those 
aperatures.  I'd make those 6-o'clock apertures double, to make them