Hello Donald,
I suggested you learn by doing it yourself. Sometimes you learn from your
mistakes. I made a mistake saying the sine changed to cosine in the southern
hemisphere. I realized this error soon after clicking "send" button. For the
southern hemisphere, the sign changes + to- but the s
Hello Donald,
Three degrees of longitude is 12 minutes of time, 4 minutes per degree, 60
minutes (1 hour) per 15°, 24 hours per 360°. Your longitude is 153 East. You
see the sun 12 minutes before the the time zone meridian. Solar noon, when the
sun is above your longitude, is 11:48 zone time, o
(I hit the wrong button in my last email and it went out without my letter-
sorry!)
Hi Donald:
I understand your question, because I had this same question years ago when
I was a beginner.
The answer is no.
To re-phrase your question so that everybody understands it, you are asking
From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On
Behalf Of Donald Christensen
Sent: Wednesday, February 09, 2011 3:52 PM
To: sundial@uni-koeln.de
Subject: part 2 of longitude correction
I'm laying out lines for a new dial
I may not have been clear. I don't inte
No, see previous reply.
A horizontal dial hour line angles are:- arctan( tan(longDiff +
hourFromNoon*15) * sin (lat) )
the relationship of longitude difference to hour line angle involves the sine
of the latitude, and only as the sine of the latitude approaches 1, as when
approaching the po
What is rotated by the longitude difference is only an equatorial or an
armillary dial. The resulting horizontal or vertical or whatever dial that
results from its surrogate equatorial dial will then have correct hour line
angles.
The "old wive's trick" only works for lattitudes as they approa
I'm laying out lines for a new dial
I may not have been clear. I don't intend to rotate the gnomen. The dial
will still point true north
By labeling 12:12 as noon and 13:12 as 13:00, I am rotating the hour marks.
My question is,
Is it by an even 3 deg?
--
Cheers
Donald
0423 102 090
This e-ma
Moreover, simply *rotating* the sundial will not correctly apply a
longitude correction; the hour lines must be re-calculated to maintain
accuracy. So, it is better to simply make the correction arithmetically
(constant throughout the year).
Larry
On 2/9/2011 2:05 PM, Willy Leenders wrote:
Make no effort, Donald.
Let your sundial be a sundial.
The longitude correction turns your sundial to a watch.
But you've already a watch.
Solar time - you do'nt have it - can only be given by your uncorrected sundial.
Willy Leenders
Hasselt in Flanders (Belgium)
Visit my website about the sundi
How do I design a longitude correction in my sundial?
Correct me if I'm wrong
My horizontal dial is for Brisbane. The longitude is 153 deg and the
standard meridian is 150. This is a 3 deg difference.
I'll then rotate the hour lines by 3 deg to compensate
--
Cheers
Donald
0423 102 090
This
Hello All,
I also have a representation of many of the Spectra sundials I have made
over the years on my web site. You can see the World of Artisan Sundials
here:
http://www.artisanindustrials.com/world-of-sundials/artisan-sundials-world.h
tml
The page requires a small Google Earth plug-in to
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