Re: Timing

[Slawomir K. Grzechnik]

At 12:35 AM 9/27/96 -0100, you wrote:

One of the fascinations of dialling for me is the still-unexpected richness 
of the field, going beyond, as it does,  the simple matter of an alternative 
to a clock. On this latter point, a clock is used for telling the time but 
also for measuring elapsed time - as an egg-timer does. Does anyone know of 
a gnomonic method or device to measure short periods of time (say, four and 
a half minutes) separately from telling the time ?



I think the most accurate method for telling short time, is a Meridian Line
or similar instrument. If the Gnomon is very hight (say many meters) the
spot light on the floor goes slow, and you can mesure minutes and seconds. 
   In San Petronio church of Bologna, the Gnomon is 27,07 meters. In the
Winter Solstice the spot light has a velocity of 0,314 meters in a minut.


I once mentioned here that there is a fellow sundialer among us who can
perform such measurements with extreme precision and using much shorter
gnomons. His name is Bill Maddux. I do not dare to publish his method even
if I am sure he would not mind. He has the privilege to do it himself. Hey
Bill are you listening? I am really sure that your method is worth
publication if not pattenting.

And paying the tribute to our ancestors. They were able to obtain quite a
precision thanks to their wits, patience and long bases of measurement.






- Slawek Grzechnik

Re: Timing

[Giovanni Paltrinieri]

One of the fascinations of dialling for me is the still-unexpected richness 
of the field, going beyond, as it does,  the simple matter of an alternative 
to a clock. On this latter point, a clock is used for telling the time but 
also for measuring elapsed time - as an egg-timer does. Does anyone know of 
a gnomonic method or device to measure short periods of time (say, four and 
a half minutes) separately from telling the time ?



I think the most accurate method for telling short time, is a Meridian Line
or similar instrument. If the Gnomon is very hight (say many meters) the
spot light on the floor goes slow, and you can mesure minutes and seconds. 
   In San Petronio church of Bologna, the Gnomon is 27,07 meters. In the
Winter Solstice the spot light has a velocity of 0,314 meters in a minut.

Ciao Giovanni Paltrinieri
Gnomonista in Bologna Italy

Re: Timing

[Peter Hirtle]

One of the fascinations of dialling for me is the still-unexpected richness 
of the field, going beyond, as it does,  the simple matter of an alternative 
to a clock. On this latter point, a clock is used for telling the time but 
also for measuring elapsed time - as an egg-timer does. Does anyone know of 
a gnomonic method or device to measure short periods of time (say, four and 
a half minutes) separately from telling the time ?


If you use some optics to give you a sharp image it is easy to see a few 
seconds of solar motion.  Maybe that is out of the realm of gnomonics?

Peter


--
 Peter Hirtle   [EMAIL PROTECTED]   Seattle, WA.