Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die eigentliche Nachricht steht dadurch in einem Anhang.
This message was wrapped to be DMARC compliant. The actual message text is therefore in an attachment.
--- Begin Message ---All Scottish (& English?) lighthouses had a sundial - how else would they set their clocks and thus turn on their lights at the correct time! Here is… 1852 General Order to Scottish Lighthouse Keepers The Principal Keeper shall go to the Sun-dial, when the sun is shining, and shall watch until the shadow touches any hour. The Assistant shall stand on the balcony, waiting a signal from the Principal. The Principal shall then make the signal; on seeing which, the Assistant shall immediately set the Clock. The Principal shall then take a note of the Equation-of-Time engraved on the Sun-dial. He shall afterwards proceed at once to the Lightroom where he shall put the timepiece back or forward… Best wishes Kevin > On 12 Jul 2018, at 20:56, Steve Lelievre <steve.lelievre.can...@gmail.com> > wrote: > > > > My recent visit to Shetland took in the recent summer solstice, allowing me > to experience for myself how Shetland's summertime sunsets are very late and > sunrises are corresponding early. Daylength at the solstice was around 19 > hours, with (civil) twilight taking up another 3½ hours or so. > Here is a photo I took of a sundial at the Eshaness Lighthouse (60.489314°N > 1.627209°W). Unfortunately it's on private property, so I couldn't get close > enough to read the the little plaque. The current lighthouse was completed in > 1929 so I guess the dial may be that early too. > > In Shetland the sun doesn't go anywhere near the zenith even at midsummer so > I was surprised by the height of the gnomon. It's just asking to be dinged, > but Shetlanders are good and gentle folk so there no sign of vandalism; just > a bit of rust and corrosion. > > I wonder why the dial spans only 12 hours? I have seen a number of other > dials that only cover 12 hours but I've never really questioned that > attribute before. Of course in this case they've stuck the dial where the > nearly building obscures the sun late in the day, so evening hours don't > really matter. That aside, surely we should expect a dial made for such a > northerly location to reflect the extreme summer daylengths? There is plenty > of open space nearby where the dial could have been sited to accept sunlight > throughout the summer evenings. > > To me it seems a trivial matter to design a dial that covers the full > midsummer daylength. Can anyone justify, or at least explain, the 12 hour > limit? > > Steve > > <eshaness.jpg> > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
--- End Message ---
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
