John and all,
I actually do think a number of small, boring sticks don't look half as inviting
to our average testosterone loaded kid as a prominent, well-shaped big one. But
I also admit that the idea of producing something unusual also appeals to me.
The dial I have in mind will be placed on a free-standing, high and narrow
'billboard' on the roadside outside my garden. I think about 250x60cm is a good
size. It should contain several small 'sundials' (hours since sunrise,
daylength, maybe altitude of the sun), plus a no-parking sign. (sigh ...)
They all need a rod-style gnomon, but I'd rather divide them into different
dials to avoid confusion of the general public, and to stress that a 'sundial'
is an astronomic instrument rather than a boring old timekeeper.
The multignomon 'time' dial could be spread all over the place, though some
logic in arranging the hourlines would probably make it more attractive.
The material I plan to use are Exterior Laminate Decor panels
http://www.fundermax.at/max_exterior_|_individual_decor.en.72.htm
weaterproof and ready to drill. You can supply your layout to the factory.
Thanks for all the suggestions about drilling holes, but I'd rather not go into
this. The panels also are not thick enough to glue the gnomons in.
But Dave Bells idea of bent gnomons sounds promising. Some thought would have to
go to the jig, since the dial is not even facing south ...
The other solution I'll investigate are shadow plane sundials. If I am not
mistaken, I could use perpendicular gnomons if they would not have to stand on
the hourline itself. So I would have to add extra lines, but construction would
be much simpler. I also think I do like the look of perpendicular gnomons better.
I would like to thank my informal think-tank, but I can feel much
head-scratching ahead ;-)
Hannes
John Carmichael schrieb:
Dear Hannes,
You said in your first email that your reason for wanting multiple gnomons
was to avoid vandalism.
I can't see why a vandal would find a multiple gnomon dial less inviting
than a single gnomon dial. But let's assume you are right.
You also said that this would be a wall dial.
Wall dials that are above the reach of humans are some of the most
vandal-resitant of all sundials. How high will the dial be? Is it out of
reach?
Thx
John C.
-----Original Message-----
From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On
Behalf Of Frank King
Sent: Monday, June 13, 2011 1:01 AM
To: "H. Kühtreiber"
Cc: sundial@uni-koeln.de
Subject: Re: Multignomon Sundial
Dear Hannes,
Your problem is turning into a bed of nails...
...the dial I had in mind would be vertical
and facing south-east...
That makes the problem more interesting!
... I can see no way, with my limited abilities,
to get the angles of all those gnomons right.
Any ideas?
I imagine that all your gnomons are going to be
the same. If you can get ONE right you can get
all the others right! Here are two questions:
What kind of gnomon you would use if you were
making a conventional dial with ONE gnomon?
How would you would attach it to the dial?
You seem to want some kind of rod gnomon. You
can attach that either by drilling a hole or by
making up some kind of mounting.
It is very difficult to drill a hole that isn't
perpendicular to the surface being drilled. It
is probably easier to make some kind of mounting.
You calculate the sub-style height in the usual
way and then design a simple mount. You then
go into mass production.
All the gnomons have to point in the same direction
so you have to have the sub-styles parallel.
There is one interesting constraint that you
DON'T have...
Your hour-lines don't have to radiate from the
same point. You could arrange your sundial on
a tall thin column with the hour-lines running
down, in order, from top to bottom, say from
4h to 14h for a dial that declines south-east.
More interesting still, you could have a
24-sided post with the 6h hour-line on the
side that faces east and the 12h hour line
on the side that faces south and so on.
I have a final piece of advice...
If you really want to drill lots of holes
at awkward angles you are going to need
some kind of jig. I cannot think of a
good way to design this jig but I am sure
there are other list members who can help.
All the best
Frank King
Cambridge, UK
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