"Slawomir K. Grzechnik" wrote: > Hello Fernando > > The shortest answer would be to have the cylinder with the dial on its > outside and few styles around it so that at least one is working. The > cylinder should be inclined so that is is parallel to the Earth axis. Then > you would have longest expositions. On the poles it would work half a year > continuously, on the Equator half a day.
In fact I have always wanted to put some styles in a cylindric water tank I have im my small farm. I have lacked the time (and certainly the expertise) to do so. But it is vertical, not inclined. > The best would be to experiment on the spots of interest :-) > This is good but hard to do. - fernando > or use Fer's program which allows for fast calculations of dials for any > latitude, orientation and inclination. For each lat you could perform few > experiments for inclinations ranging from 0 (horizontal dial) to 90 > (vertical) and see how the length of the exposure changes. If you made > systematic research you could publish it because that would be of interest. > > > All best > > Slawek > > At 07:54 AM 8/11/99 -0300, you wrote: > >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 > > > > > > > Slawek Grzechnik > 32 57.4'N 117 08.8'W > http://home.san.rr.com/slawek -- 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
