On Fri, Oct 2, 2015 at 6:12 AM, Willy Leenders <willy.leend...@telenet.be> wrote:
> Dan, > > What I mean is this: > > 1. > Together with the sundial on the roof is given the EOT table. > What can you do with it? > Well, you can add the EoT table entry to the time shown on the sundial, to get standard time. > As a result of the empirical way of construction on September 1 you can, > using the EOT table, determine the standard Eastern European Time on > other days. > On any day, yes. Of course, that's clear from what the original-poster said. > Specifying the length correction you could also determine the true local > time > Yes, you could get local true solar time by adding or subtracting 4 minutes to the sundial's reading for each degree of latitude east or west of the place's time-zone's central meridian. As for the choice of local true solar time, or true solar time at the central meridian, both dial-marking systems are frequently, widely, used. Which you use is a matter of individual preference. Either you mark the dial for true solar time at the central meridian, or you incorporate the longitude correction in the EoT table. Both methods are popular. > > 2. > To indicate the standard Eastern European Time you have many options: > clock, cell phone, computer ... > There's no need to a sundial. > Sundials have aesthetic value. Though they can often be of practical time-telling use, that isn't their only justification. Yes, a sundial marked in true solar time at the central meridian is, by implication, intended or emphasized for practical use. > Indicating the true local time is only possible on a sundial. > Let him do it ! > Yes, that's one valid preference, one vaild choice. But both choices are valid. Yes, I personally like a sundial to give local true solar time, and incorporate the longitude-correction in the EoT table. That's how I made my pocket-portable tablet-dials. Nevertheless it must be accepted that not everyone makes the same choice that we make, and that many sundials are marked in true solar time at the central meridian. Michael Ossipoff On Fri, Oct 2, 2015 at 6:12 AM, Willy Leenders <willy.leend...@telenet.be> wrote: > Dan, > > What I mean is this: > > 1. > Together with the sundial on the roof is given the EOT table. > What can you do with it? > As a result of the empirical way of construction on September 1 you can, > using the EOT table, determine the standard Eastern European Time on > other days. > Specifying the length correction you could also determine the true local > time > > 2. > To indicate the standard Eastern European Time you have many options: > clock, cell phone, computer ... > There's no need to a sundial. > Indicating the true local time is only possible on a sundial. > Let him do it ! > > > Willy Leenders > Hasselt in Flanders (Belgium) > > Visit my website about the sundials in the province of Limburg (Flanders) > with a section 'worth knowing about sundials' (mostly in Dutch): > http://www.wijzerweb.be > > > > > > > Op 1-okt-2015, om 22:06 heeft Dan-George Uza het volgende geschreven: > > Willy, > > I'm sorry but I did not quite understand your message. The dial is > supposed to show standard Eastern European Time, not true local time. The > longitude correction for Bistrita is already built in the hour marks > because they were empirically drawn according to the watch when EoT was 0. > Therefore the correction table only deals with variations in Eot. > > Dan > > On Thu, Oct 1, 2015 at 10:55 PM, Willy Leenders <willy.leend...@telenet.be > > wrote: > >> A nice project for the decoration of the roof ! >> However, it is not possible to read the true local time. >> And one can not deduce it for the place at longitude: 24° 30′ 3.82′′ E >> (Bistrita) with only the table for EOTas a tool. >> >> >> Willy Leenders >> Hasselt in Flanders (Belgium) >> >> Visit my website about the sundials in the province of Limburg (Flanders) >> with a section 'worth knowing about sundials' (mostly in Dutch): >> http://www.wijzerweb.be >> >> >> >> >> >> >> >> Op 1-okt-2015, om 21:24 heeft Dan-George Uza het volgende geschreven: >> >> Dear group, >> >> I am happy to be able to share a picture of the first Romanian reclining >> sundial built recently by Damaschin Berende, a friend from a neighboring >> town. It's made of plywood, it sits on a roof and it features both a EoT >> correction table and interchangeable hour marks for winter time and >> daylight saving time. Reported accuracy is so far around 1:30 min. >> Direction of gnomon across the roof was fixed by taking a plumb bob shadow >> reading >> from the base of the gnomon at local noon, the elevation angle was >> calculated according to the latitudine and the hours were marked on the >> shadow during September 1st, when EoT was 0. I especially like the wooden >> pole etched with traditional solar motifs and the rooster on top. You can >> view more photos here: >> >> http://cerculdestele.blogspot.ro/2015/10/sine-sole-sileo-ceasul-solar-inclinat.html >> >> Please also consider it for the Sundial of the Month on >> http://sundialatlas.eu using ID no. RO000023. >> >> Regards, >> >> Dan Uza >> <sine sole sileo -.jpg> >> --------------------------------------------------- >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> >> >> > > > -- > Dan-George Uza > http://cerculdestele.blogspot.com > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > >
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