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  • Very interesting, but sounds like an extra complication to use binary search on time to find the right position of the sun, when you can just directly calculate this, eg. using the formulas in here: https://gml.noaa.gov/grad/solcalc/solareqns.PDF
    by tcumulus
  • Various apps for (primarily) photographers offer views of the sun's (and moon's) path, even with live view through the camera.

    For example https://www.sunsurveyor.com/ or https://www.photopills.com/ best among others

    by jcynix
  • It would be good to also have the option for alignment with sunrises in addition to sunsets.

    For instance in Houston the sunrise aligns with Texas Avenue around the June solstice.

    Consequently, there are no sunset alignments for the downtown skyscrapers.

    by fuzzfactor
  • I lived a long time in a city near the equator with a prominent east-west street. Commuting west to east in the morning and east to west in the evening meant frequent hengings. The roads don't feel particularly safe when you can't see anything. The town planners might have considered this.
    by normie3000
  • Interesting, I've planned similar shots before and used different tools that serve a similar purpose. The Photographer’s Ephemeris has nice visualizations: https://photoephemeris.com/

    NASA's Horizons ephemeris is also pretty good at preparing data for this. I've used it with a little script to check when the sun/moon will be in a given box. This hengefinder looks neat and really streamlined for its purpose though.

    by pierrec
  • It uses the Python lib Astral, which uses "equations from Astronomical Algorithms, by Jean Meeus", to find location of the Sun in the sky. That method assuming earth motion without gravitational pull from other planets or the Moon, and has accuracy of 0.01 arc degree. Meeus is a rock star in these kinds of calculations. He also gave a truncted version of VSOP87 that has error less than 1 arc second in finding Sun's location.

    The method Astral uses for calculate Moon's location has precision of 1 arc minute. For higher precision, LEA-406 [1] can be used.

    [1] https://www.aanda.org/articles/aa/full/2007/33/aa7568-07/aa7...

    by infinet
  • I need the inverse of that - an app that predicts how badly a given street will be baked by the sun at current or near-future time, will there be any shadow zone from the buildings, how far will the usable extent of it reach (e.g. not much use of shadow if my head or body stick up beyond the shaded volume). Ideally available on a smartphone. Bonus points for being able to route navigation paths to minimize direct sun exposure.

    Motivation: I hate it when it's hot, but my kid has actual issues with heat/sun exposure, and e.g. I had to navigate our way around the city through shaded zones today, just so she doesn't get exhausted in under 30 minutes.

    Plenty similar apps are made to sell people photovoltaics, but I'd love to see something to help humans avoid sun.

    by TeMPOraL
  • It would be nice to be able to access the website on a smartphone (even if the experience is suboptimal), instead of denying access.
    by lefra

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