At 07:14 AM 9/1/99 -0400, Mac Oglesby wrote:
>
>I wonder what it would take to make it a sundial showing hours until dark.
>That is, how would the time of "dark" (relative to sunset) be determined?
Hi Mac,
This is an excellent challenge.
First, we have to define "dark". Bowditch defines Civil
horizon to the western horizon one may read off the hours that the sun is
above the local horizon.
As I recall, maritime twighlight is determined by the sun being less than 7
degrees below the horizion.
This angle may be approximately read on my dial and thus the time of total
darkness may be read.
Dan
> At 07:14 AM 9/1/99 -0400, Mac Oglesby wrote:
> >
> >I wonder what it would take to make it a sundial showing hours until
dark.
> >That is, how would the time of "dark" (relative to sunset) be determined?
>
Hello Mac,
in
