"heiner thiessen" <[EMAIL PROTECTED]> quoted me as saying To: "Sundials Mail List" <[email protected]> Sent: Sunday, June 22, 2003 5:49 PM Subject: Re: Sundials at Pole
> > Steve, > > You missed Gianni's point, wonderfully expressed, that there is a point at > > the pole at which the height of the sun does not vary during the day. If > the > > height of the sun varies during the day, you are not at the pole. You > might > > be only a metre away, but that's not close enough. <snip> > Chris, > Am I not right in thinking that at the pole itself, > the height of the Sun spirals either up (from spring > equinix to summer solstice) or down (from summer solstice > to autumn equinox), if only so marginally that you > may find it difficult to measure the daily increments, which are due to the > changes in the Sun's declination? But the 'fine threads' of that spiral > seem to suggest that, strictly speaking, the altitude of the Sun during > that one day does change, if only marginally. Or am I making a mistake here? > Heiner Thiessen > 51 00 43 N > 00 56 38 W No mistake, and I'm sorry if I seemed to suggest otherwise. Yes, indeed, even at the poles the sun's altitude varies with the declination, which varies continuously. And this gives the basis for measuring the seasons - you can determine the summer solstice and the equinoxes. But during a day it gives no hint as to when is midday or midnight - meaningless terms - or which direction is the meridian - they all are. Chris Lusby Taylor 51.4N, 1.3W -
