Hi Jim et al, I don't know about you, but I find time stops still when I see a beautiful sunset like that. Who cares exactly what time it is?
If the cloud/haze was thick enough to allow you to look at the sun I doubt if it would have cast a usable shadow, in any case. So just enjoy it. Perhaps the apparent widening was an instance of the well-known psychological effect whereby the moon appears bigger when near the horizon, or perhaps refraction due to temperature gradients. Five minutes later all sundials would stop working. By the way, even moon dials will stop working for a time on Wednesday night. Don't miss it (though in the UK it's rather late - about 3:15 to 3:40am). The last total eclipse for several years. Not visible in Australia or east Asia, I'm afraid. Best wishes Chris ----- Original Message ----- From: "J. Tallman" <[EMAIL PROTECTED]> To: "'Chris Lusby Taylor'" <[EMAIL PROTECTED]> Cc: "Sundial Mailing List" <[EMAIL PROTECTED]> Sent: Monday, February 18, 2008 8:31 PM Subject: RE: Monumental Sundial Hi Chris and All, Yesterday evening I was driving south on the interstate and saw a fabulous sunset where the sun was incredibly magnified...even before it got right down on the horizon. There were thin clouds that cut the light enough for me to observe the disk, and it sure did look wide. How would an apparently larger solar disk like that affect the gnomon/distance ratio and the shadow width characteristics on a tubular polar style, say, with the resultant shadow landing on the inside of an equinoctial ring where the receiving surface is parallel to the gnomon? The dark umbral part of the shadow would be diminished, right? I wonder if that effect should be factored in when choosing the ratio to use in determining the optimum diameter of a tubular gnomon? Best, Jim Tallman www.artisanindustrials.com [EMAIL PROTECTED] 513-253-5497 --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
