[{"data":1,"prerenderedAt":121},["ShallowReactive",2],{"blog-en-surya-a-clock-that-follows-the-sun":3},{"id":4,"title":5,"body":6,"cover":35,"date":105,"description":106,"draft":107,"extension":108,"locale":109,"meta":110,"navigation":111,"path":112,"seo":113,"stem":114,"tags":115,"__hash__":120},"blog\u002Fblog\u002Fen\u002Fsurya-a-clock-that-follows-the-sun.md","Surya, a clock that follows the sun instead of the time zone",{"type":7,"value":8,"toc":96},"minimark",[9,13,24,30,37,42,45,48,52,55,58,64,68,71,74,78,81,85,93],[10,11,12],"p",{},"Three in the afternoon in July and three in the afternoon in December are two completely different times. One means you have half a day of light left. The other means you should probably start walking home. Your watch shows the same number for both, and that started to bother me more than it should have.",[10,14,15,16,23],{},"So I built ",[17,18,22],"a",{"href":19,"rel":20},"https:\u002F\u002Fapps.apple.com\u002Fde\u002Fapp\u002Fsurya-time-sun-clock\u002Fid6804929118?l=en-GB",[21],"nofollow","Surya Time",", a sun clock for the iPhone. It doesn't replace the clock you already have. It sits next to it and answers a different question: where am I in today's daylight?",[25,26],"portrait-image",{"alt":27,"caption":28,"src":29},"Surya's main screen with a circular dial showing 40.01 percent of the solar arc, plus time spent, time left and sunset","The main dial. Forty percent of today's sun is gone, seven hours and fifty-five minutes are left.","\u002Fimages\u002Fblog\u002Fsurya\u002Fsun-left.jpg",[31,32],"youtube-embed",{"caption":33,"id":34,"poster":35,"title":36},"A short film about Surya Time: a clock that tells the time from the sky.","sEvFzEaK_ig","\u002Fimages\u002Fblog\u002Fsurya\u002Fcover.jpg","Surya Time: a clock that tells the time from the sky",[38,39,41],"h2",{"id":40},"twelve-hours-of-daylight-whatever-the-season","Twelve hours of daylight, whatever the season",[10,43,44],{},"The main screen is a dial. Surya takes your daylight from sunrise to sunset and divides it into twelve natural hours, the way sundials did before railways forced everyone onto the same clock. In summer those hours stretch. In winter they shrink. Either way, the sixth hour is always the middle of your day.",[10,46,47],{},"If that feels too old-fashioned, you can switch the dial to a plain percentage. \"40 percent of the sun is gone\" turns out to be a surprisingly useful sentence. Under the dial you get the numbers in normal clock time as well: how long the sun has been up, how much is left, and when it sets.",[38,49,51],{"id":50},"the-horizon-is-not-flat","The horizon is not flat",[10,53,54],{},"Most weather and sun apps give you sunset for a perfectly flat horizon. I live near the Alps. Down here the sun never sets at the official time, it vanishes behind a ridge half an hour earlier and the valley goes blue while the peaks are still orange.",[10,56,57],{},"Surya pulls real elevation data for the terrain around you and draws your actual skyline. The sun sets where it sets in real life, behind the hills, ridges and peaks you are looking at. That was the feature I wanted most.",[59,60,61],"blockquote",{},[10,62,63],{},"Your watch shows the same three o'clock in July and December. The sun doesn't.",[38,65,67],{"id":66},"finding-a-bit-more-light","Finding a bit more light",[10,69,70],{},"The Vantage Map came out of that horizon work. It shows nearby lookouts and ridges and works out how much extra sunset you get if you climb up there before dusk. Sometimes it's a few minutes. Sometimes it's enough to make the walk worth it.",[10,72,73],{},"Because you usually want that information exactly where your phone has no signal, you can save the terrain around you before you leave, in a radius of 30, 60 or 200 km. Out on the trail the skyline and the sun calculations keep working offline.",[38,75,77],{"id":76},"small-extras","Small extras",[10,79,80],{},"There are five widget styles for the home and lock screen, so you can glance at the sun without opening anything. Surya shows true solar noon for your coordinates and how far your watch is off from it, which in a wide time zone can be a lot more than you'd guess. And if the moon is hiding behind clouds or trees, you can hold the phone up and a pointer shows you where it is.",[38,82,84],{"id":83},"quiet-on-purpose","Quiet on purpose",[10,86,87,88,92],{},"No account, no login, no ads, no tracking, no analytics running in the background. All the astronomy runs on the phone. Your location is used on the device to calculate your sun and never sent anywhere. The ",[17,89,91],{"href":90},"\u002Fen\u002Fsurya-privacy","privacy page"," says the same in more formal words.",[10,94,95],{},"Surya costs 0,99 € once and runs on iPhone. It's a small app with one job, and it's the first thing I open when someone asks if we still have time for a walk.",{"title":97,"searchDepth":98,"depth":98,"links":99},"",2,[100,101,102,103,104],{"id":40,"depth":98,"text":41},{"id":50,"depth":98,"text":51},{"id":66,"depth":98,"text":67},{"id":76,"depth":98,"text":77},{"id":83,"depth":98,"text":84},"2026-09-01","I built a small iPhone app that tells you how much daylight you have left, where true solar noon is for your exact spot, and when the sun really disappears behind the mountains in front of you.",false,"md","en",{},true,"\u002Fblog\u002Fen\u002Fsurya-a-clock-that-follows-the-sun",{"title":5,"description":106},"blog\u002Fen\u002Fsurya-a-clock-that-follows-the-sun",[116,117,118,119],"Surya","iOS","Side Project","Apps","BMNEHL8MYeZSOPSyHMtbcXrpHFSTpH5ARAhgO4KtvHM",1792165383093]