Hi Andrew,
As Bob Terwilliger pointed out, I made a sundial out of a wall satellite dish
some years ago. I published the results and method in:
J. Davis: Satellites and sundials, BSS Bulletin, 11(ii), pp.77-80, (1999).
My dish was one of the old Astra analogue ones and was a pe
Hi Andrew,
The easiest and quickest way combined to lay out sundials on arbitrary
surfaces is by either a string or a laser trigon. A variety of sundials can be
used as models in order to transfer the hour and date lines to the surface.
There have been a number of articles on this in the NASS
[mailto:[EMAIL PROTECTED] On Behalf Of John Carmichael
Sent: Thursday, June 21, 2007 6:57 PM
To: 'Willy Leenders'
Cc: 'Sundial List'
Subject: RE: Direct South Dial
Dear Willy
Im not sure I agree with you. I think the
empirical method automaticly corrects for the
longitude s
To: 'Willy Leenders'
Cc: 'Sundial List'
Subject: RE: Direct South Dial
Dear Willy
Im not sure I agree with you. I think the
empirical method automaticly corrects for the
longitude shift. If you mark the shadows
location using a watch on a day when the EOT is
zero, the
>
>
>
> -Original Message-
> From: Simon [illustratingshadows
> [mailto:[EMAIL PROTECTED]
> Sent: Thursday, June 21, 2007 1:34 PM
> To: Willy Leenders; John Carmichael
> Cc: 'Sundial List'
> Subject: Re: Direct South Dial
>
> John's me
quot;
http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search?analemma
_
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of John Carmichael
Sent: Thursday, June 21, 2007 6:57 PM
To: 'Willy Leenders'
Cc: 'Sundial List'
Subject: RE: Direct South Dial
Dear Willy
Im not s
el
Cc: 'Sundial List'
Subject: Re: Direct South Dial
John's method does mark legal time and thus does
consider longitude.
However, unless I am more than usually dense today, it
provides hour points for a given declination, not hour
lines.
However, it has been a long day, so I may simply
Carmichael
Cc: 'Andrew Corl'; 'Sundial List'
Subject: Re: Direct South Dial
Hi John,
Using your empirical method, not only the equation of time must be zero, you
have to take in account the correction for longitude.
Willy Leenders
Hasselt in Flanders (Belgium)
Op
John's method does mark legal time and thus does
consider longitude.
However, unless I am more than usually dense today, it
provides hour points for a given declination, not hour
lines.
However, it has been a long day, so I may simply be
denser than usual:)
Simon
--- Willy Leenders <[EMAIL PRO
Hi John,
Using your empirical method, not only the equation of time must be
zero, you have to take in account the correction for longitude.
Willy Leenders
Hasselt in Flanders (Belgium)
Op 21-jun-07, om 21:24 heeft John Carmichael het volgende geschreven:
Hello Andrew:
There is an easy w
Dear Andrew,
Many satellite dishes are made from perforated metal sheet. Is yours
similarly partially transparent?
If so, a basic vertical dial can be drawn on a flat sheet (declining if
necessary) and then sight through the dish onto the flat sheet and
transfer the hour lines by eye 'forward
Hello Andrew:
There is an easy way to mark the hourlines on a satellite dish or any
surface for that matter, without using any formulas or math. Use what some
call the empirical method. This method is useful for oddly shaped
surfaces.
1. Position the dish in the direction that you want
While Willy is absolutely correct, the part about knowing and computing
for the shape of the dish is probably the real killer task.
This is an application where I would advocate the empirical approach:
Properly orient the dial face and style, then manually lay out points,
with a watch in hand. Pla
Hi Andrew,
you have to orient the disc to the south
you have to decline the disc to a vertical position
on a vertical and south oriented plane behind the disc you have to
work out (virtually) the hour lines and date lines of a vertical
south oriented nodal sundial - the node must be a part of
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