...@uni-koeln.de] On
Behalf Of Helmut Sonderegger (Tele2)
Sent: 05 April 2010 20:23
To: Sundial Mailing List; Mac Oglesby
Subject: Re: Fwd: how italian hours
Hello,
to add an additional feature. I calculated with my software
Italian/Babylonian hours in shepherds' dials: Babylonian hours from 0 to
7
Dear Chris,
Your diagram is a masterpiece!
I still find it intriguing that
the simple-to-define concepts of
Babylonian and Italian hours open
the way to a feast of geometric
delights.
With you dreaming up such eloquent
mappings, this feast clearly has
more courses to come!
All the best
Frank
Dear Mac,
I like your H2SS Card.
You say...
My foolish thought was that every
golfer and hiker and outdoors
person would want this information.
Not so foolish! They DO want this
information but maybe you were
marketing it in the wrong place
and to the wrong group...
The big snag with
much time they
have vasted already in the morning when they get up later (;-)
Helmut Sonderegger
- Original Message -
From: Mac Oglesby ogle...@sover.net
To: Sundial Mailing List sund...@rrz.uni-koeln.de
Sent: Monday, April 05, 2010 12:16 AM
Subject: Re: Fwd: how italian hours
Hello
Warren:
here's a dial that shows the current position of the Sun. It's an Oughtred
Dial on a gnomonic projection (instead of the stereographic that Oughtred
used). I've also added the current sunset/sunrise terminator and the area of
the globe that is currently illuminated (ignoring refraction,
Just realized I'd neglected to add the SML to the distro.
Brad
-- Forwarded message --
From: Brad Lufkin bradley.luf...@gmail.com
Date: Sun, Apr 4, 2010 at 9:29 AM
Subject: Re: Fwd: how italian hours
To: Warren Thom thom...@gmail.com
Cc: LISTA INGLESE sund...@rrz.uni-koeln.de
Hello Friends,
Warren's message jogged my memory to recall an article which he, Fer
de Vries, Bill Maddux and I published in the September 1998
Compendium about A Card Dial With Italian Hours.
Following that article I continued to play with H2SS designs and
produced a pocket size H2SS card
: Sunday, April 04, 2010 3:16 PM
To: Sundial Mailing List sund...@rrz.uni-koeln.de
Subject: Re: Fwd: how italian hours
Hello Friends,
Warren's message jogged my memory to recall an article which he, Fer
de Vries, Bill Maddux and I published in the September 1998
Compendium about A Card Dial
Dear Gianni and Roger,
Thank you very much for the clarifications.
Gianni's table is especially clear about
the two cycles of 12 for Italic hours as
used in the Muslim world.
Chris Lusby Taylor's comment is true in a
way but, equally, your original remark can
be interpreted as being correct.
In Ottoman Sundials we find often the Italic hours because these hours give
the time to the sunset, when the Muslims must say the Prayer Maghrib.
These hours are given not from 0 (sunset) to 24 (sunset of the next day),
but, as Roger has written, in two cycles of 12 hours and are called Ezanic
All,
I have enjoyed the discussion about Italian hours. My first dial was an
hours to sunset dial on my garage door done in the 1970s. Mac Oglesby's
models and dials are inspiring to me. I had a globe parallel to the earth
in the 1980s that I liked to view on a sunny day. I could
I drew several sundials with conic gnomon or sphere inscribed in a cone, to
show italian and babilonian hours of different places.
For example, the picture shows a sundial for 12 european cities. Every cone
has a different vertex angle, depending on the latitude of the city, and
casts a shadow
Dear Gianni,
Your analysis has silenced the Lista Inglese!
I will summarise what you said so that new
readers may start here...
You have:
D = length of day (sunrise to sunset)
Whenever D is an integer number of hours, the
associated constant-declination curve passes
through a hyperbolic
Dear Roger,
You are right...
This gets more interesting with each note.
The business of labelling gnomonic features
elegantly can be a nightmare!
With an ordinary sundial you have a chapter
ring of one kind or another for the labels of
the hour-lines and life is straightforward!
When you try
Chris Lusby Taylor,
has very kindly written me that in my first Email *“How trace the italic
hour lines” *I have made an error: it’s true!
The error is serious enough and I thank Chris and apologize to all L
I wrote
*Also for each point of the line of horizon (on the sundial) pass one
Sorry , I forgot the table :-)
Gianni F.
TabOre.pdf
Description: Adobe PDF document
---
https://lists.uni-koeln.de/mailman/listinfo/sundial
...@rrz.uni-koeln.de;
frank.k...@cl.cam.ac.uk
Subject: Re: how italian hours
Dear Roger,
You are right...
This gets more interesting with each note.
The business of labelling gnomonic features
elegantly can be a nightmare!
With an ordinary sundial you have a chapter
ring of one kind
Greetings, fellow dialists,
Re my suggestion of laying out an italian hours dial ninety degrees
away: Did you ever feel, the moment after you had hit the send button,
that you should not have written what you did? Of course, it would not
work. But I am pleased that the subject of italian and
2010 09:58
To: Sundial
Subject: re how italian hours
Greetings, fellow dialists,
Re my suggestion of laying out an italian hours dial ninety degrees
away: Did you ever feel, the moment after you had hit the send button,
that you should not have written what you did? Of course, it would not
work
Hello friends,
I've been following the discussion about Italian hours sundials with
great interest, since dials with Italian hours labeled in countdown
fashion have been a passion of mine for many years.
The focus of the discussion has been on dials where the Italian hour
lines appear as
Dear Gianni,
I enjoyed your explanation and (I liked
the deliberate mistake which you included
to make sure we were paying attention)...
If we have a horizontal sundial we
cannot use the method that I have
described yesterday.
Of course, we CAN use your yesterday's
method provided we accept
*Some other curious properties of the Italic and Babylonian hours.*
I will adopt here the Frank’s notation : F=French or modern hours;
I=Italic; B=Babylonian.
Moreover T=Temporary and D = duration of the clear day (from dawn to
sunset).
The simple following formulae are valid:
Dear Frank,
You pose two questions:
1. How do you lay out Babylonian and
Italian hour-lines?
2. Why use dubious definitions of
sunrise and sunset?
I attend to the dubious definitions below
but let's live with them for a moment.
BABYLONIAN AND ITALIAN HOUR-LINES
Let B =
Dear Jack,
You go straight to the heart of the matter...
I was struck by the fact that the Italian and
Babylonian hours coincide (cross each other)
at the equinox line but not at the solstice
lines.
It is, of course, these criss-crosses which
make having the Babylonian+Italian hour-lines
Sent: Monday, March 29, 2010 6:47 AM
To: Sundial
Subject: how italian hours
Greetings, fellow dialists,
Following the pictures of the fine dial of Frank King in Selwyn College,
Cambridge (congratulations) I began to wonder how it was laid out. Most
of the commonly consulted books on dial
Dear Gianni,
I like your explanation and I like the
extra comments too.
You have:
P1 on the equinoctial line and
P2 on the horizon line
This is good in theory but not so
good in practice. For example, my
line for Bab = 11 does not run
as far as the equinoctial line or
the horizon
Greetings fellow dialists,
I am a bit closer to understanding the laying out of Italian hours,
thanks to correspondents. Jan Safar wants to instruct me in a method
using an oblique gnomonic projection. Although I can just about cope
with astrolabes and Weir's azimuth diagram I think I would
frankev...@zooplankton.co.uk
Sent: Monday, March 29, 2010 3:47 AM
To: Sundial sund...@rrz.uni-koeln.de
Subject: how italian hours
Greetings, fellow dialists,
Following the pictures of the fine dial of Frank King in Selwyn College,
Cambridge (congratulations) I began to wonder how it was laid
A small addition
If we have a horizontal sundial we cannot use the method that I have
described yesterday.
In this case, however, the point where the Modern hour line HMOD and the
Italic hour line HIT=2 HMOD cross the horizon line becomes a “point
to infinity” (I hope that this is the
Roger Bailey wrote:
The conversion of the
presentation to an article fro the compendium is stalled at 80% complete.
This follows the classic 80 20 rule defining work progress.
Which is to say that the remaining 20% of work will consume the *other*
80% of time?
Dave
Greetings, fellow dialists,
Following the pictures of the fine dial of Frank King in Selwyn College,
Cambridge (congratulations) I began to wonder how it was laid out. Most
of the commonly consulted books on dial construction (in English),
Waugh, Mayall Mayall, Cousins, etc. do no more than
dear Frank,
I use the trigonometric sphere.
I get the formula for the angle (alpha) between the max slope line and the n
italian line, then the distance (s) of the italian line from the base of the
orthostyle O.
The formula is for any oriented dial.
I attach:
- the trigonometric sphere: P is
Of Frank Evans
Sent: Monday, March 29, 2010 6:47 AM
To: Sundial
Subject: how italian hours
Greetings, fellow dialists,
Following the pictures of the fine dial of Frank King in Selwyn College,
Cambridge (congratulations) I began to wonder how it was laid out. Most
of the commonly consulted books
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