sundial,
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Andrew,
Wanted to make sure you got this email that I sent to the list.
Richard
=
Robert, John, Willy, and All,
Using a satellite dish as a sundial is a great
idea. And a fully functioning dish with hour
markings could work as a satellite re-aiming tool
- Since a working
Robert, John, Willy, and All,
Using a satellite dish as a sundial is a great
idea. And a fully functioning dish with hour
markings could work as a satellite re-aiming tool
- Since a working dish that is locked into place
and then marked with hour lines could be used to
re-aim the dish aft
John
yes, the polar axis aligned style would generate the
dial center and thusly the hour lines. Heck I did that
with one of my large wall dials where the wall was an
irregular surface. Duh.
Good to know I am not the only one not thinking well
today:)
Simon
--- John Carmichael <[EMAIL PROTECTED
This reference strays a bit from the topic, but this chap has a method (and
a program for sale) which will aim a dish at a satellite using a
quasi-sundial approach.
http://www.sundialsetup.com/
Also John Davis made what I believe was a decliner recliner from a satellite
dish. Perhaps he will ch
Hi Simon:
Thanks for confirming that the empirical method autocorrects for longitude
shift.
You wrote:
However, unless I am more than usually dense today, it
provides hour points for a given declination, not hour
lines.
I think that if the gnomon is a polar axis rod (not a perpendicular one)or
i
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, then the longitude correction is there.
The sundial will be marking watch time when the EOT is ze
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
Greetings all,
Several months ago I bought a house and the previous owners left me with one
of those 12" diameter satellite dishes. I have no need or want of Direct TV or
satellite TV.
I was sitting there thinking one day that it would make a really nice direct
south facing sundial.
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