Isocahedric Sundial - Parametric Latitudes

prusaprinters

<p><i>This kind of spherical sundial is called a “scaphé”.</i></p><p><i>It is a very precise sundial that can be used to determine date and hour.</i></p><p>&nbsp;</p><p><strong>Choose the sundial adapted to your latitude :</strong></p><ul><li>54° : Leeds (GB) - Hamburg (DE) - Minsk (BY) - Edmonton (CA)</li><li>51° : London (GB) - Praha (CZ) - Kiev (UA) - Calgary (CA)</li><li>48° : Paris (FR) - München (DE) - Wien (AT) - Quebec (CA) - Seattle (US)</li><li>45° : Torino (IT) - Vladivostok (RU) - Ottawa (CA) - Minneapolis (US)</li><li>42° : &nbsp;Barcelona (ES) - Roma (IT) - Istanbul (TR) - Sapporo (JP) - New-York (US)</li><li>39° : Lisboa (PT) - Athens (GR) - Beijing (CN) - Washington (US)</li><li>6° : Lome (TG) - Colombo (LK) - Bogota (Bo)</li></ul><p>&nbsp;</p><p><strong>How to use the sundial ?</strong></p><ul><li>Put it on a flat and horizontal surface and orientated to the North.</li><li><strong>Use the top of the shadow</strong> to read date and hour.</li></ul><p>&nbsp;</p><p><strong>Use it to know the date :</strong></p><ul><li>The upper line is the Winter Solstice (December 21st)</li><li>The downer line is the Summer Solstice (June 21st)</li><li>The middle line is the Equinoxes (March 21st / Sptember 21st)</li></ul><p>&nbsp;</p><p><strong>Use it to know the hour :</strong></p><p>You will need to correct the solar time if you want to know the UTC.</p><ul><li>Add 1h in Winter and 2h in Summer if you have a seasonal correction of the time (such in West Europe)</li><li>Add (west) or remove (east) a correction according to the distance with your reference meridian (10min for 200km at 45° latitude)</li></ul><p>&nbsp;</p><p><i><strong>Praha :</strong> +1h (Summer) / +0 (Winter) - <strong>Paris : </strong>+1h50 (Summer) / +50min (Winter) - <strong>Torino :</strong> +1h30 (Summer) / +30min (Winter) - <strong>Istanbul :</strong> +1h</i></p><figure class="image image_resized" style="width:47.45%;"><img src="https://media.prusaprinters.org/media/prints/68832/rich_content/0601843d-0bfa-4d2d-9c53-12ebff30449c/img_1615.jpg#%7B%22uuid%22%3A%220118c0a0-01f0-4f78-8bfa-f7d851d9c21f%22%2C%22w%22%3A5152%2C%22h%22%3A3864%7D"></figure><p><i>Example : June 10th in Dinan (West France / 48°) : 18h20 (solar) + 2h (Summer) + 10min (west of meridian) = 20h30 UTC</i></p><p>&nbsp;</p><p><strong>Use it to measure the Solstices :</strong></p><ul><li>During the Winter Solstice, at 12h (solar time) the light will go through the 3 "horizontal" upper holes. You should see a light point on the table behind the sundial.</li><li>During the Summer solstice, at 12h (solar time) the light will go through the “vertical” hole.</li></ul><p>&nbsp;</p><p><strong>Print Settings :</strong></p><ul><li>Printed on MK3S</li><li>Filament tested : PLA</li><li>Scale : from 66% to 200%</li><li>Nozzle 0.4mm : 0.15mm and 0.20mm tested</li></ul><p><i>Prusa Slicer 2.3.0</i></p>