Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Patrick Powers
Sent: October 17, 2005 8:22 AM
To: SundialList
Subject: Re: equation of time
Message text written by "Frans W. Maes"
>Much older is a very elaborate copper horizontal dial, engraved around
1730
by Davi
Message text written by "Frans W. Maes"
>Much older is a very elaborate copper horizontal dial, engraved around
1730
by David Coster, now in the Rijksmuseum (Amsterdam-4 in the book, with
picture). It has analemmas for all hours from 8 to 16.<
Hi Frans, this gets more and more interesting! Thanks
Dear Frank & all,
[Sorry, previously sent to Frank only]
The Dutch sundial catalog (Zonnewijzers in Nederland, by Van Cittert-Eymers
& Hagen) mentions as the oldest public analemma in the country: an analemma
carved in stone at a sundial on a house in Jutphaas (south of Utrecht) from
1831 (cat.nr
Roger,
> I think the lack of equation-of-time indicators on dials before the
> mid-1800s has a simple explanation: Sundial time was considered
> CORRECT, and the mean solar time shown by clocks WRONG (or, at least,
> a mere approximation).
Well, I suppose there was some kind of
uot; time; but, I come at this from a different
direction. I wonder if you will please re-post those discrepancies, as
noted above, but with the DATES appropriate to the discrepancies,
or corrections. I ask this because I am interested in knowing whether the
Equation of Time (EOT) was calculate
came from the first Astronomer Royal, John Flamsteed. Tompion himself also put EoT tables on some of his dials but he didn't usually date them - the earliest which is positively datable is around 1702 but there may be ones from the 1690s.
For further details, see:
J. Davis: The Equation of
At 11:16 AM 10/12/2005 +0100, Frank Evans wrote:
>My question is: Was this, like Richardson's appendix in Mrs. Gatty's
>book, a first appearance of an equation of time line? Can anyone supply
>earlier earlier examples of such a line on dials either in the UK or
>elsewhere?
Greetings fellow dialists
Re the earliest analemma on a dial in the UK nothing has turned up
before the 1889 example cited by Chris Daniel but thanks to Franz Maes,
Dave G. and Tony Moss for helping the problem along. Early equation of
time corrections engraved around the edge of horizontal
Dave G. wrote:
>Lloyd Mifflin (sp?) obtained a US patent for a sundial with an analemma in
>or around 1867
USA patent No. 64,892 of 21st May 1867 to be exact although it wasn't the
familiar full 'figure 8' shape he used. Two profiled plates, each
covering six months of the analemma, were fitte
- Original Message -
From: "Frank Evans" <[EMAIL PROTECTED]>
To: "Sundial"
Sent: Wednesday, October 12, 2005 3:16 AM
Subject: equation of time
> Greetings fellow dialists
>
> In his recent article on the equation of time in BSS Bulletin 17 (i
Greetings fellow dialists
In his recent article on the equation of time in BSS Bulletin 17 (iii),
Chris Daniel writes that the earliest appearance of the analemma in a UK
publication is perhaps the illustration in the second edition of Mrs.
Gatty's sundial book, dated 1889. Here the f
ion to calculate the Equation of Time If you note the parameters to
this function you will see that latitude is not necessary for calculating
it.
David
-Original Message-From:
[EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of dougdotSent: Wednesday, 16 October 2002 7
Hello all,
As a newcomer to dialling, I would like to know
whether the "fast" or "slow" as shown on the graph is the same for the southern
hemisphere as for the northern hemisphere.
Doug
Hello all,
on Sat, 4 Jan 1997 I sent a message to this list with the results of a
little research on the definition of the Equation of Time.
I send it again (only partly) after having revised the results (extended
to new books..)
I've searched for EoT on many books on Sundials a
Hello all,
Ooops!... Of course, I make a mistake:
>For example in France, traditionally: EoT = real time - mean time
>while in USA: Eot = mean time - real time.
Please read:
For example in France, traditionally: EoT = local mean time - solar time
while in USA: Eot = solar time - local mean time
Dear all,
I would like to know how the equation of time (EoT) is defined according to
country.
For example in France, traditionally: EoT = real time - mean time
while in USA: Eot = mean time - real time.
Could you tell me how you define the Eot in your country ?
Many thanks
Yvon
Yvon
Oops! Sorry about the banal error, and most grateful for all the
comments. Fortunately nothing was carved in stone, and the sign error
has now been corrected.
Other points:
1. The incorrect "Equation of Time" has now been relabelled "Standard
Time Correction" and it is
rom:
Gianni
Ferrari
To: sundial@rrz.uni-koeln.de
Sent: 01 May 2001 16:13
Subject: Solar Noon & Equation of
Time Calculator
Hi Piers ,I have visited with a lot of interest your Solar
Noon Calculator on the webat www.solar-noon.com and I have immediately
made some tests
Even if, already from two centuries, in all the nations, engineers and
scientists have tried of to reach an unification of the different quantities
that are used in industry and in science and hundreds of International
Conferences have been made for adopting the same definitions all over the
worl
ONE JOT what convention is actually used so
> long as the end result is correct, explained and understandable to others
> of a different persuasion.
>
> The difference in the preferred usage of the sign of the Equation of Time
> has been known for so long that we need to be able to
of a different persuasion.
The difference in the preferred usage of the sign of the Equation of Time
has been known for so long that we need to be able to accommodate it, not
try to change it.
It is no different to the use of different weights or temperature scales.
There will always be those str
On Tue, 1 May 2001, Steve Lelievre wrote:
> Gianni wrote:
> > As in almost all Web sites, also you take as positive the Longitudes for
> > places West of Greenwich.
> > The Explanatory Supplement to the Astronomic Almanac (USNO 1992) at page
> > 203 affirms:
> > "The geocentric longitude is
Gianni wrote:
> As in almost all Web sites, also you take as positive the Longitudes for
> places West of Greenwich.
> Despite the opinion of the known astronomer J. Meeus, with which also
Davis
> agrees in his Sundial Glossary, even if a secular tradition justifies this
> definition, it is NO
e not to call it Eot
Moreover in this way the table with the values of noon is useless because
these values are equal to those of the EoT + 12h
The definition :
"Equation of Time displays the difference between solar time and the
standard times where you are"
(note at the foot of the
have a links
page if you would like a reciprocal link.
You can also get a printout of the Equation of Time in the same format.
We hope this will be useful. We would appreciate your comments.
The page was developed as part of the Spot-On Sundial project (see
www.spot-on-sundials.co.uk
Dr J R Davis
Flowton, UK
52.08N, 1.043E
email: [EMAIL PROTECTED]
- Original Message -
From: Gordon Uber <[EMAIL PROTECTED]>
To: sundial
Sent: 27 November 2000 07:35
Subject: Needed: history of equation of time
> I have become interested in the history of the Equation of T
Hello Gordon,
I possess a small book about EoT, mostly old tables.
Tables of the Equation of Time
for the Regulating of Clocks and
Watches by a Sun-Dial
Ex Libris
Christopher St. J.H. Daniel
1993
Mr. Daniel is the chairman of the BSS.
Best wishes, Fer.
Fer J. de Vries
[EMAIL PROTECTED]
http
recommend a reference (preferably in English) on the subject?
I understand that John Flamsteed and Christiaan Huygens published tables of
it in 1666 and 1662, respectively. If anyone has copies of these tables,
the tables (or citations to them) would be greatly appreciated.
So far I have loc
I think this modeling explanation is as close as you'll get to a conceptual
view of the question (without mathematics or technical terminology). Here are
some of the thoughts I've had about this type of visualization problem.
1. You could take a purely observational view and say, Haven't you not
pears to move
in a eastward direction and at a variable rate. If the Sun's apparent
motion eastward is variable then so to is the length of our apparent
solar day. The daily variation in the length of our solar day is
additive, the sum of which is the Equation of Time.
The question th
plane of the earth's orbit.
Please can anyone explain me the second cause so that I can conceive it. I
am not a astronomer!
If you have a globe that's tilted 23.45 degrees from vertical in its stand,
and you spin it, that's its rotational plane, the plane of its equator.
If you move the
Willy
Simply put,
the actual sun moves irregularly in the ecliptic plane,
the mean sun may be thought to move uniformally in the earth's equatorial
plane.
In the first the ellipse is involved, in the second the obliquity of the
earth's axis is involved.
Dan Wenger
>The equatio
Willy Leenders <[EMAIL PROTECTED]> writes:
> The equation of time has two causes. The first is that the orbit of
> the earth around the sun is an ellipse and not a circle. The second
> is that the plane of the earth's equator is inclined tot the plane
> of the earth'
The equation of time has two causes. The first is that the orbit of the earth
around the sun is an
ellipse and not a circle. The second is that the plane of the earth's equator
is inclined tot the
plane of the earth's orbit.
Please can anyone explain me the second cause so that I ca
"Ron Anthony" <[EMAIL PROTECTED]> writes:
> If I gave you a nice looking but somewhat erraticatic watch (the dial), and
> said, "It works good but its 10 minutes fast". You would have no problem
> making the mental calculation to get the correct time.
I think you're right that native English
Whitaker's Almanack says "The direction in which the equation of time
has to be applied in different problems is a frequent source of confusion and
error." I think the confusion has little to do with any difference between
navigators and astronomers. I think it had more
Fellow Shadow Watchers
Current discussions Re.the Equation of Time bring to mind Tad Dunne's
contribution to the Great Sundial Motto Festival of 1998 - or World War
III depending on how you remember it :-)
Hope you don't mind me re-printing you Tad!
"On September One, you ca
Message text written by Frank Evans
> but for navigators EoT has always been mean time minus apparent
time. My
British Admiralty Manual of Navigation, Volume 2, 1938 states simply:
The equation of time is defined as the excess of mean time over apparent
time.<
I have just looke
- Original Message -
From: Krzysztof Kotynia <[EMAIL PROTECTED]>
To: Rudolf Hooijenga <[EMAIL PROTECTED]>
Sent: Saturday, September 25, 1999 11:34 AM
Subject: Re: Equation of Time Graph wrong way up Down Under ?
> > While that in itself is commendable, I re
I don't know if Patrick Powers is right about astronomers differing from
(sextant age) navigators regarding the sign of the equation of time but
for navigators EoT has always been mean time minus apparent time. My
British Admiralty Manual of Navigation, Volume 2, 1938 states simply:
The equ
CTED] (office)
- Original Message -
From: John Hall <[EMAIL PROTECTED]>
To:
Sent: Friday, September 24, 1999 4:22 AM
Subject: Equation of Time Graph wrong way up Down Under ?
> Can somebody please shed light on a problem I have encountered with the
> standard graph of the Equa
Fellow Shadow Watchers
With regard to confusions arising from the Eqation of Time I was in
ToolMart recently where they were selling a particularly repellant fake
cast dial which must have been inspired by a genuine item for it carried
a circular Equation of Time setting out corrections
n Hall <[EMAIL PROTECTED]>; sundial
Date: Friday, September 24, 1999 1:12 AM
Subject: Equation of Time Graph wrong way up Down Under ?
>This is a common problem. Historically there have been two ways of
>assigning the positive and negative signs to the Equation of Time. It all
>d
This is a common problem. Historically there have been two ways of
assigning the positive and negative signs to the Equation of Time. It all
depends on the way you think of the difference of the two entities that
give rise to the EoT.
I think (but am not entirely sure) that navigationalists
Can somebody please shed light on a problem I have encountered with the
standard graph of the Equation of Time.
I have used the routines by Fer de Vries to generate the graph and the print
outs check out perfectly with all standard references. They all indicate
that at this time of the year the
Hi Pete,
Thanks very much for your help in calculating the "average over 4
years-sort of" analemma as shown in your
http://netnow.micron.net/~petes/sundial/dialcalc.htm. Luke Coletti
also sent me a really helpful table off-list.
And I like your Bi-Millennial figures-of-eight, indicating th
My apologies for such late input to this thread, I have been a little behind
in my e-mail! I encountered many of these problems and the same questions
when designing my Analemmic Equatorial sundial
( http://netnow.micron.net/~petes/sundial ). I hope the following
will help.
Luke Coletti wrote:
t;[EMAIL PROTECTED]>
Subject: Re: Equation of Time
References: <[EMAIL PROTECTED]> <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=us-ascii; x-mac-type="54455854";
x-mac-creator="4D4F5353"
Content-Transfer-Encoding: 7bit
Thanks, John for telling of the situ
Thanks to Tom Semadeni for his kind words:
>Thanks to Chris, for the clever graphical explanation showing especially the
>discontinuities which support his recommendation to look at John Shepherd's
>work on the beautifully designed and executed Richard D. Swensen Sundial
>at the
>University of Wi
Hello,
Below are some data that may help you, the calculation date is
Jan 1 Noon UT, EoT values are in the form TA-TM. The value of the EoT
corresponds to a date/time i.e., a calendar and since there is not a
whole number of days in our orbital period I think you can see how the
EoT becom
nalemma must have an error due to leap years. The error can
> > be avoided.
> >
> > It is true that tables of the Equation of Time are slightly inaccurate
> > because they take a mean value for the solar longitude on a named date (such
> > as February 17th), whereas th
Thanks to Chris, for the clever graphical explanation showing especially the
discontinuities which support his recommendation to look at John Shepherd's
work on the beautifully designed and executed Richard D. Swensen Sundial at the
University of Wisconsin - River Falls.
http://www.uwrf.edu/sund
ying that an analemma must have an error due to leap years. The error can
> be avoided.
>
> It is true that tables of the Equation of Time are slightly inaccurate
> because they take a mean value for the solar longitude on a named date (such
> as February 17th), whereas the 4 year an
AIL PROTECTED]) is only partly correct in
>saying that an analemma must have an error due to leap years. The error can
>be avoided.
>
>It is true that tables of the Equation of Time are slightly inaccurate
>because they take a mean value for the solar longitude on a named date (such
Dear dialers,
Tom Semadeni <[EMAIL PROTECTED]> asks for clarification of a few points in
my earlier mail.
Firstly, I stated that an EoT table would have most error in 1903 and 2096.
The only factor I was considering was indeed the difference between the
calendar year and the mean tropical year. T
Chris Lusby's post is instructive and I'd like to learn more.
Chris Lusby wrote:
> It is true that tables of the Equation of Time are slightly inaccurate
>
> because they take a mean value for the solar longitude on a named date
> (such
> as February 17th), wherea
Daniel Wegner ([EMAIL PROTECTED]) is only partly correct in
saying that an analemma must have an error due to leap years. The error can
be avoided.
It is true that tables of the Equation of Time are slightly inaccurate
because they take a mean value for the solar longitude on a named date (such
>I'm looking for the analytical solution of equation of time. I'm trying to
>study the revolution motion of the earth around the sun and I'd like to
>find the relationship between the analytic solution of this motion and the
>equation of time...
>
>Bye
>Tom
I'm looking for the analytical solution of equation of time. I'm trying to
study the revolution motion of the earth around the sun and I'd like to find
the relationship between the analytic solution of this motion and the equation
of time...
Bye
Tom (ITALY)
-
Free e-mail g
Indeed, and for those without access to Her Majesty's Stationery ;) the current
convention is (Apparent Solar Time - Mean Solar Time) often abbreviated TA-TM.
Luke
Krzysztof Kotynia wrote:
> There is a convention about the sign of the eqt.
> It was adopted by IAU (International Astronomical Uni
> I was wondering if there was a convention about the sign of the equation
> of time. Waugh describes 'dial fast' and 'dial slow' but doesn't have a
> sign. His graph looks negative in February. I want to make a graph that
> is positive in February and negati
inking is often the reverse (?inverse) of navigational thought.
Good Luck
DAVE
Lat 33º 39' N Long 118º 04'W [ by my own sights and subject to
correction ! :) ]
John Harding wrote:
> I was wondering if there was a convention about the sign of the equation
> of time.
To John Harding's question concerning the sign of the equation of time
there is, for navigators of ships at least, a simple answer. Any
instructional book on nautical astronomy will say that the equation of
time is defined as mean time minus apparent time, i.e. clock time minus
sun time.
I was wondering if there was a convention about the sign of the equation
of time. Waugh describes 'dial fast' and 'dial slow' but doesn't have a
sign. His graph looks negative in February. I want to make a graph that
is positive in February and negative in November and I
Dear friends,
I could read only few days ago the many messages that have been
sent to
the List regarding the development of the Equation of Time in Fourier series.
I thank in particular John Pickard to have taken up again the matter and
Fer de Vries and Luke Coletti to have
***
>From: "Gianni Ferrari" <[EMAIL PROTECTED]>
>To: "sundial list"
>Subject: Equation of Time
>Date: Tue, 31 Dec 1996 19:25:02 +0100
>
>Dear friends,
>I've followed with much interest the several messages
>arrived in last days
John Pickard wrote:
> Over the past few months there have been several discussions of
calculating declination and equation of time. I have seen no > > mention
of using Fourier series to do this.
>
> In 1971, an Australian physicist workin on building research wrote a
brief pap
John Pickard wrote:
>
> Greetings all,
>
> Over the past few months there have been several discussions of
> calculating declination and equation of time. I have seen no mention
> of using Fourier series to do this.
>
Yes please, place it on the sundial
Greetings all,
Over the past few months there have been several discussions of
calculating declination and equation of time. I have seen no mention
of using Fourier series to do this.
In 1971, an Australian physicist workin on building research wrote a
brief paper on how to do these
Nicelli Alberto wrote:
> Hi all brothers dialists!
> Who knows the exact time and the exact ecliptic longitude of the
> earth's perihelion ?
The time(s) of perihelion and the other three principle orbital
positions can be found at the following URL:
http://aa.usno.navy.mil/AA/data/docs/Ear
--
From: Nicelli Alberto[SMTP:[EMAIL PROTECTED]
Sent: terça-feira, 9 de dezembro de 1997 13:55
To: 'sundial@rrz.uni-koeln.de'
Subject: Equation of Time Formula
Hi all brothers dialists!
Who knows the exact time and the exact ecliptic longitude of the
earth&#x
See "Astronomical Algorithms" by Jean Meeus, published
by Willmann-Bell. He has a chapter on the Equation of Time.
Formulas and parameters for almost everything astronomical.
See: http://www.willbell.com/
Gordon
At 14:55 97/12/09 +0100, you wrote:
>Hi all brothers dialists!
&
Hi all brothers dialists!
Who knows the exact time and the exact ecliptic longitude of the
earth's perihelion ?
I need these values to calculate myself the Equation of Time with this
formula I've obtained with a simple and traditional recipe : a little
bit of spherical geometry a
** I read about this list on the "Sundials on the Internet" page by the
BSS. **
Hello Frank, and all,
As for the _name_, I think "equation" can mean something done, or
needed, to equate a thing to something else.
As Fer said, ' Can it be a translation of "Equatio Temporis"? '
Personally I would
I have a photocopy of William Molyneux' "Sciothericum Telescopium" Dublin
1686, and can confirm that he uses the term "Equation of Time". The title
of Chapter X is "Concerning the Astronomical Equation of Time and the Tables
thereof":
"Being now upo
quot; was printed as early as 1683
for Thomas Tompion. - from "The Grandfather Clock" by Earnest
Edwardes.
Gordon Uber
At 08:37 97/10/13 +0100, you wrote:
>I know WHAT the equation of time is.
>What I would like to know is - WHY is it called that?
>Isn't an equation supposed to
Frank Tapson wrote:
>
> I know WHAT the equation of time is.
> What I would like to know is - WHY is it called that?
> Isn't an equation supposed to contain an equals (=) sign?
> Surely it is really a correction factor?
> Should it not go something like:
> Local Mean
I know WHAT the equation of time is.
What I would like to know is - WHY is it called that?
Isn't an equation supposed to contain an equals (=) sign?
Surely it is really a correction factor?
Should it not go something like:
Local Mean Time = Local Apparent Time + Correction
Anyone know any
separate sheet with the NASS bulletin vol.4
nr. 2. He mentions the year 1672)
And in the Netherlands we have Christian Huyghens.
You see, every country its own inventor .
I point to a source by Christopher St.J.H. Daniel, chairman of the BSS.
Tables of the Equation of Time, for the
I have recently discovered the newsgroup about sundials. Here is a text
in complement of the last message of C. Lusby-Taylor about the equation of
time. Hoping it will contribute to the debate.
As for myself I am of course interested in sundials from all points of
view. I
Before the pendulum, clocks were not accurate enough to compete with a
sundial, and there was little point in trying to set a clock or watch to
other than solar time, but the difference was certainly known.
Tables of the equation were published and sometimes engraved on sundials or
pasted inside t
ers had a time piece available much more accurate
than a water clock or a mechanical clock: the motion of the stars. As
I tried to make clear before, it is not necessary to decide whether
the sun or the stars move more regularly in order to discover the
equation of time. The only tricky part is obse
is technically
known as the "equation of time."" "It is characteristic for the high level
of hellenistic astronomy that a correct determination of this correction was
achieved. We do not know to whom it is due this important step in the
theory of time reckoning: in the sources
Arthur,
Observing the length of the sidereal day (a stars transit) and
comparing it to the length of the solar day (the suns transit) seems to
me a very good suggestion for a possible method employed. If these daily
differences were measured and then summed an equation of time connecting
Concerning the question of when the analemma, which I interpret to be
equivalent to the equation of time, was discovered and how: We think
of the equation of time as expressing the relationship between the
position of the sun and "real time", but there is also a direct
astronomical inte
Dear all,
In a message to Gianni Ferrari I wrote about the change in the
definition for EoT by the IAU in 1930.
But I made typing errors.
The formal definition was EoT = TM - TA.
In 1930 changed into EoT = TA - TM.
TM is mean time
TA is local time.
Sorry for my errors.
Fer.
At 17:57 03/01/97 +0100, Gianni Ferrari wrote:
>Warren Thorn wrote :
>
>> With the help of the basic programs from Sky & Telescope, I have
>> worked on the question of how many full moons will fall on Christmas
>> in the next 100 years. (3-2015,2072,2091) Someone at church said
>> we would not ha
[EMAIL PROTECTED] wrote:
>
> Thanks for the informative GIF which compares the EOT for 1902 and 2098.
>
> Two questions:
>
> 1. What drawing program did you use to make the GIF. I've been wanting to
> draw a nice EOT graph for use on my website, but the only drawing program I
> have requires m
Warren Thorn wrote :
> With the help of the basic programs from Sky & Telescope, I have
> worked on the question of how many full moons will fall on Christmas
> in the next 100 years. (3-2015,2072,2091) Someone at church said
> we would not have a full moon on Christmas for over 100 years---I
>
Ross McCluney wrote:
.
> EOT = .170 sin (4*pi*(J - 80)/373) - .129 sin (2*pi*(J - 8).355)
>
> where the arguments of the sine functions are in radians and J is the
> number of days since December 31, and EOT is given in decimals hours.
> .
Dear Ross,
I received your formula for the EoT
Prof Gregorio,
>>0-360 degrees (and NOT 0-3600 degrees); it was probably a misunderstanding,
due to e-mail transmission.<<
Yes, that was the problem. I used Charles Gann's copy of the formula. For
July 27, 1980 at 12:00 I got -6m 27.6s. This compares to -6m 25.4s I got
using the longer fo
At 15:55 30-12-96 -0800, you wrote:
>Well, I started to join in in the EoT calculation fun,
>following Francois Blateyron's original question. I began
>by implementing his equations in a spreadsheet, as he did.
>I used Microsoft Excel...
>
>With Robert Sinnott's correction to the longitude of per
Ron Anthony wrote:
>
> Prof Gregorio,
>
> >> As far as the Equation of Time is concerned, the last
> edition of the Explanatory Supplement to the Astronomical
> Almanac reports (pag. 484) the following algorithm:<<
>
> Thank you for the algorithm. No matte
François BLATEYRON wrote:
>
> Hi dear gnomonists...
>
> Can someone help me with the calculation of the equation of time ?
Dear François,
I beg your pardon for my delay, but I have been very
busy in the last hours, since I have been shovelling
snow away..
I agree with the Roge
>Date: Wed, 01 Jan 1997 05:11:37 -0500
>To: "Gianni Ferrari" <[EMAIL PROTECTED]>
>From: [EMAIL PROTECTED]
>Subject: Re: Equation of Time
>
>At 07:25 PM 12/31/96 +0100, you wrote:
>
>>EoT= E0+E1*cos(wt+F1) + E2*cos(2wt+F2) +.. + E6*cos(6wt+F6)
>>
At 07:35 PM 12/31/96 +0100, you wrote:
>Dear gnomonists,
>
>In this e-mail I have attached a gif-picture of the curve of the
>equation of time for two years, 1902 and 2098.
>They are calculated with the formula ( for the mentioned years) I
>mentioned in my earlier e-mail this
Gianni Ferrari wrote:
>
> Dear friends,
> I've followed with much interest the several
> messages arrived in last days on EoT calculation.
I too, find this discussion interesting. It also requires us to
ask "What is significant?" in effects on time measurement.
So far we have ce
Prof Gregorio,
>> As far as the Equation of Time is concerned, the last
edition of the Explanatory Supplement to the Astronomical
Almanac reports (pag. 484) the following algorithm:<<
Thank you for the algorithm. No matter how hard I try I cannot
make the algorithm yield the cor
Dear gnomonists,
In this e-mail I have attached a gif-picture of the curve of the
equation of time for two years, 1902 and 2098.
They are calculated with the formula ( for the mentioned years) I
mentioned in my earlier e-mail this day.
You see the ( small) change in the curve in a periode of
Dear friends,
I've followed with much interest the several
messages arrived in last days on EoT calculation.
I've nothing to add to what the authors have written but I will
note that the long calculation described not always are useful
if we wont only design a sundial.
The Sun
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