Chris, Two remarks and a question:
1. Remark 1 A sundial is not an analemmatic sundial because it contains an analemma (an 8-shaped curve) indicating the relationship between date (declination of the sun) and EOT. An analemmatic sundial consists usually of a horizontal dial face with an elliptic perimeter, on which the hour points are located. The major axis of the ellipse runs east-west. A date line is set along the minor (north-south) axis. A vertical gnomon is placed on the correct date. The time is read from the point where the shadow (or its extension) intersects with the ellipse. Its name is a word derived from the Greek 'ana lemma'. That means 'view from above'. The analemmatic sundial is a view from above or projection of an equatorial sundial. 2. Remark 2 The name 'Digital' is misleading It only means here that the time is shown in figures such as a digital clock. 3. The question Can the sundial also indicate the real local time (solar time)? If not then this is a missed opportunity. The sundial then indicates what you already can see on your watch. 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' (in Dutch): http://www.wijzerweb.be Op 10-nov-2010, om 21:28 heeft Chris Dobbie het volgende geschreven: > Just in the last week I’ve become fascinated with sundials and decided to > join this mailing list. This is my first post here and with that said I’d > like to say hello to all members and ask that you forgive my noobish > questions. > > I saw a “digital” equatorial sundial for the first time the other day and > fell in love with its simple design, just a band of metal bolted to a rock. I > soon realized that its simplicity came with a cost to functionality. I’ve > since come up with a far less simple design that I think solves most > functionality problems including equation of time and the inability of use > between 6 pm and 6 am. > > You can’t really tell from the model but I envision the equatorial ring being > able to rotate 360 degrees with markers along its track for longitude and DST > correction as well as current times for other cities around the world. One > could also make it universal by marking it in degrees and making the base > adjustable. If build large scale, minute lines could be added to the analemma. > > I’ve only recently started researching sundials and the math of the analemma > is still confusing me so I have a couple questions. I imagine if I > calculated out the amalemma and checked the time at noon this dial would be > fairly accurate but how accurate would it be at dawn and dusk? Would the > angels of the analemme change? Also, would rotating the equatorial ring > affect accuracy? If the dial does work and the amalemma and dial were marked > in smaller increments, how accurate do you think it would be? > > Lastly, I’m wondering if you have ever seen this style of dial before in > design or finished form? I have yet to come across one and would love to see > any pictures or info that’s out there. Thank you so very much for any and all > you can share with me. > > Cheers, > > Chris > > <finished dial (Custom).jpg> > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
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