Is it sunrise or sunset with an offset?

[rocfusion]

Hi Pontus,

The when is an optional parameter,  so you you can then ask for the sunset \ sunrise for next Tuesday.    Your rscalc function is different to mine.  Here is mine which is from the Feb 2015 release of the firmware.

Thanks,

Roger

Code:

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-- sunrise / sunset calculation function rscalc(latitude, longitude, when)  local pi = math.pi  local doublepi = pi * 2  local rads = pi / 180.0  local TZ = function(when)    local ts = os.time(when)    local utcdate, localdate = os.date('!*t', ts), os.date('*t', ts)    localdate.isdst = false    local diff = os.time(localdate) - os.time(utcdate)    return math.floor(diff / 3600)  end  local range = function(x)    local a = x / doublepi    local b = doublepi * (a - math.floor(a))    return b < 0 and (doublepi + b) or b  end  when = when or os.date('*t')  local y2k = { year = 2000, month = 1, day = 1 }  local y2kdays = os.time(when) - os.time(y2k)  y2kdays = math.ceil(y2kdays / 86400)  local meanlongitude = range(280.461 * rads + 0.9856474 * rads * y2kdays)  local meananomaly = range(357.528 * rads + 0.9856003 * rads * y2kdays)  local lambda = range(meanlongitude + 1.915 * rads * math.sin(meananomaly) + rads / 50 * math.sin(2 * meananomaly))  local obliq = 23.439 * rads - y2kdays * rads / 2500000  local alpha = math.atan2(math.cos(obliq) * math.sin(lambda), math.cos(lambda))  local declination = math.asin(math.sin(obliq) * math.sin(lambda))  local LL = meanlongitude - alpha  if meanlongitude < pi then    LL = LL + doublepi  end  local dfo = pi / 216.45  if latitude < 0 then    dfo = -dfo  end  local fo = math.min(math.tan(declination + dfo) * math.tan(latitude * rads), 1)  local ha = 12 * math.asin(fo) / pi + 6  local timezone = TZ(when)  local equation = 12 + timezone + 24 * (1 - LL / doublepi) - longitude / 15  local sunrise, sunset = equation - ha, equation + ha  if sunrise > 24 then    sunrise = sunrise - 24  end  if sunset > 24 then    sunset = sunset - 24  end  return math.floor(sunrise * 60), math.ceil(sunset * 60) end