This simple simulator will show you how dynamic the relation between solar time and time zone time can be. The outer ring is the time zone dial, the second inner circle is the solar time dial (sundial). Imported are the values below the sundial. You will discover, that the deviations of single time points can be very different to the absolut deviation (e.g. DST). Also, that time differences of more than 3 hours are possible… Zur deutschen Version →
The deviation of the sun’s orbit (±17 minutes) could not be considered (see also: »Equation of Time« →). Automatic DST has pnly an effect when you move the 3rd slider button into the left half. The simulation is configured for temperate zone, northern hemisphere. The parameters are approximated and have no reference Accuracy. The »distance to time zone longitude« is limited to 3 hours.
Move the distance fader to -1 hour, west. Set the day length to the left, on »summer«. At last turn the DST on [ DST on/off auto √ ]. The result are very different time deviation: no deviation in the morning, 2 hours at midday and even 4 hours in the evening.
Distance to time zone longitude …
… does NOT mean the difference between time zones themself (e.g. UTC+1 to UTC+8). It is the distance/difference between the local mean time (LMT) of the time zone longitude and the LMT of a position/location INSIDE this time zone area. In this website its usually named »Time Zone Difference«.
Westcoast south France ca. –1 hour, westcoast Portugal ca. –1,5 hour, West China ca. –3 hours, New York ca. +10 Minutes, Greenwich London ca. 0 timeunits.
Formula: (Longitude signed – (Winter time zone signed * 15 degree)) * 4 min. = Distance in minutes
Example: (–8,6854 – (1 * 15)) * 4 = –94,7416 Min. = round –95 Min. or minus 1 hour 35 min. (west/left)
The longitude is at Google Maps and Co, usually the second value. For this simulation, it is sufficient to use the Longitude only as an integer (for example, –8). Winter time zone is the actual Time zone definition. In Germany this is e.g. +1. The daylight saving time zone UTC + 2 would lead to an incorrect result.