I sent this message yesterday but it was returned.
I thought the world could be over for you guys
who tried to see the eclipse. Since it seems it didn't,
here it is again:
Given a certain latitude, how can we find the "best" angles for
a sundial?
For "best" I mean those that offer:
a) the longest insolation during the day
b) the longest insolation at the various seasons
c) the best azimuth (declination) and the best reclination so the dial
can be place as high as possible and still get to be
seen confortably (based on the angle, not on the size).
My guess is that if we are beyond 23 1/2 N or S, than
the sundial should be vertical and face South (N) or
North (S). This would give the "best" possible
angles which would allow the sundial to show every hour
from sunrise to sunset every day of the year.
Now, if it sits in-between 0 and 23 1/2, is there are
"better" angle?
For instance, Brasilia is 19d 45' 5" S (47 d 49' 59" W).
Of course, it the sundial is vertical and faces North, in December it
will
be useless. Now, the more I recline it, the longer it will work
towards the solstice in December. If I go as far as to have
horizontal, of course it will work all year round but will
not be seen if it is placed on the top of a column.
If fact, I would guess I would never have to go beyond
23 1/2 degrees of reclination.
Is this message to confusing? I think it is :-)
I am not sure I have been able to describe what I intended to
get: to place a sundial in the top of a 6-meter tall (19' 8") column
so as it can be the best possible visibility from the ground.
At the same time it should work all year round for a certain
latitude (in this case, 15 d 45' 5"S), from sunrise to sunset.
Again, it seems clear it should face North. For visibility
from the ground, the the lesser the declination, the better.
For insolation...
I hope this is less confusing now.
- fernando
- fernando
--
Fernando Cabral Padrao iX Sistemas Abertos
mailto:[EMAIL PROTECTED] http://www.pix.com.br
Fone Direto: +55 61 329-0206 mailto:[EMAIL PROTECTED]
PABX: +55 61 329-0206 Fax: +55 61 326-3082
15º 45' 04.9" S 47º 49' 58.6" W
19º 37' 57.0" S 45º 17' 13.6" W
