September 1, 1999
Hello Roger,
Thanks for your note. Judging from your other sundials, you will create a
lovely piece. Please send me a picture when/if it comes to pass.
If I was ever aware of a sidereal time option suggested by Karl
Schwarzinger, I've forgotten the details. Can you refresh my memory? Of
course, one could simply label a "normal" hours to sunset sundial as
showing sidereal hours to sunset, since the difference is slight. Cute
idea.
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?
Best,
Mac Oglesby
*** *** *** ***
>Hi Mac,
>I am finally putting to use your design manual for vertical sundials which
>show the hours to sunset. Your concept for using such a dial at an airport
>to show pilots flying VFR the number of hour till sunset was an ideal
>application. I am proposing a similar dial to the Royal Astronomical
>Society of Canada for the dark sky site of the Alberta Star Party near
>Caroline Alberta. All these amateur astronomers will be pacing around their
>scopes impatiently waiting and wondering when it is going to get dark. They
>need a dial with Italian hour lines labeled in countdown fashion to
>determine how long it is till sunset. Constructing such a dial can be my
>contribution to the club. I keep preaching to them the utility of sundials
>so this can prove my point.
>
>Thanks for providing the design information. Thanks as well to Fer de Vries
>for including Italian hour lines in the Zonwvlak program. This made the
>basic design very easy. Maybe I should also add the sidereal time option
>suggested by Karl Schwarzinger. Star time on a sundial! Now that would
>really impress a bunch of astronomers.
>
>Roger Bailey
>Walking Shadow Designs
>N 51 W 115
