John's question is a good one. Accurate determination of the solstice would
have been difficult for ancient cultures due to the low rate of change of
the declination and sunrise azimuth. The techniques suggested will work but
they require repeated observations under difficult conditions. Clear ski
At 08:25 AM 12/21/01 +1100, David Pratten wrote:
>Dear Walter,
>
>Greetings.
>
>There is another factor which limits sundial accuracy to about +/-22
>seconds. This is the variation in the value of Equation of Time from
>year to year within a leap cycle. See
>www.sunlitdesign.com/infosearch/sun
Dear Walter,
Greetings.
There is another factor which limits sundial accuracy to about +/-22
seconds. This is the variation in the value of Equation of Time from
year to year within a leap cycle. See
www.sunlitdesign.com/infosearch/sundialaccuracy.htm
David
www.sunlitdesign.com
-Origin
A very merry Christmas to all the diallists!
John Schilke
Hello again, thank you for all for the reactions, but what is wrong with my
feeling about a second, when I say you can feel it , I mean of course you
can count in seconds & not in milli- or nano- seconds. I had thought about
the sharpness of the shadow, but forgotten to mention it. Considering the
I do have a slw connection and an ooold computer but, AS FAR AS
I AM CONCERNED,
please keep sending SMALL images: they are nice and sometimes MUCH more
explanatory than a whole
paragraph.
But, well, maybe Robert is right and it would be a politer idea to post the
URL when writing to t
Hi all,
A report in today's Daily Telegraph newspaper in the UK, says that there
are plans to build a 132 feet tall sundial in the English Midlands. It will
consist of"3 giant sails of stainless steel erected in the shape of a
pyramidwith shadows thrown by two of the sails on the third al
Hello Sundial Friends:
I am planning on making a ceiling sundial (as a project with my children in
an actual science/math application). I have the tiny lipstick mirror
mounted at my window frame (half way up), and was told that the easiest way
(void of all the mathematical calculations that th
I consider a
>second ideal as one can feel it, I mean it is a timespan well related to the
>human body, one second you live, the next you may be dead;
Walter,
This is very strange statement. True that you live one second and are dead
the next, but by the time that happens it's a bit late to st
Hi Walter,
It is not possible to increase the dimension of a sundial to increase the
precision of the reading and to reach the possibility to read intervals of
time very small.
The reason is in the diameter of the Sun, because of which when the style
goes away from the (horizontal) plane its sha
those attachments anyhow.
Thibaud Chabot
At 16:25 19-12-2001 -0500, you wrote:
I think attachments (less than 200K) are fine. The recipient can make the
choice whether to download them or not. This is a useful way to share ideas.
Bill Gottesman
--
Patrick powers is correct in noting that the 0.5 degree width of the sun
(corresponding to 2 minutes of time) creates a shadow penumbra that is
virtually impossible to read to the second. But, a sharp edge can be
achieved by a focusing dial, which creates an crisply defined image of the
sun,
Message text written by "walter.jonckheere"
>I have a feeling 1 second could be obtained<
The ability of a conventional sundial to show accurate time is usually
compromised by the half degree angle subtended at the earth by the sun's
disc. This makes shadows fuzzy and it makes it very difficult
Dear Membership,
Pardon if this is a repeat. My mail has had a couple of hiccups.
Yes, I will send no attachments. Yes, I'll post pictorial or lengthy
content on one of my websites for a while, or send it directly to
those requesting it without copying the info to the list. Bear in
mind th
Surely the whole business of finding the solstice is like a slower analogue
of finding noon by observing solar altitude?
Just around noon the altitude changes extremely slowly, and it is hardly
possible to judge the time of maximum altitude exactly. Here, today, noon
is at 12:04:49 but even if w
Greetings to all
We all know that the atomic clock has the highest possible resolution, while
for sundials 2 to 1 minute seems to be the best achievement. I have a
feeling 1 second could be obtained considering what follows. ( I consider a
second ideal as one can feel it, I mean it is a timespan w
Dear Bill, Luke, Edley, et al.,
>Is there something wrong with the list? It seems that Edley is responding to
>a message about a Dodwell dial, but I never received it.
My apologies. As Edley noted in a later not , I sent a direct
copy to Edly, and then inadvertently sent my posting
17 matches
Mail list logo
