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strawdog
Published
Edited
Dec 22, 2020
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md`# Suncalc test

This is an example to demonstrate some issues with the suncalc moon illumination algorithm`
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suncalc = require("suncalc@1")
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//https://www.timeanddate.com/moon/phases/timezone/utc
// Also verified against the US Naval Observatory list
// Jan 2020 UTC time zone
// 2020-01-03T04:45 first quarter
// 2020-01-10T19:21 full
// 2020-01-17T12:58 last quarter
// 2020-01-24T21:42 new
// Jan 2021
// 2021-01-06T09:37 third quarter
// 2021-01-13T05:00 new
// 2021-01-20T21:01 first quarter
// 2021-01-28T19:16 full

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{
let a=suncalc.getMoonIllumination(new Date('2020-01-03T04:45'));
let b=suncalc.getMoonIllumination(new Date('2020-01-02T22:15'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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{
let a=suncalc.getMoonIllumination(new Date('2020-01-10T19:21'));
let b=suncalc.getMoonIllumination(new Date('2020-01-10T15:35'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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{
let a=suncalc.getMoonIllumination(new Date('2020-01-17T12:58'));
let b=suncalc.getMoonIllumination(new Date('2020-01-17T09:27'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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{
let a=suncalc.getMoonIllumination(new Date('2020-01-24T21:42'));
let b=suncalc.getMoonIllumination(new Date('2020-01-24T12:50'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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{
let a=suncalc.getMoonIllumination(new Date('2021-01-06T09:37'));
let b=suncalc.getMoonIllumination(new Date('2021-01-06T03:05:58.020'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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{
let a=suncalc.getMoonIllumination(new Date('2021-01-13T05:00'));
let b=suncalc.getMoonIllumination(new Date('2021-01-12T20:19:29.934'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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{
let a=suncalc.getMoonIllumination(new Date('2021-01-20T21:01'));
let b=suncalc.getMoonIllumination(new Date('2021-01-20T15:13:19.914'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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// 2021-01-06T09:37 third quarter
// 2021-01-13T05:00 new
// 2021-01-20T21:01 first quarter
// 2021-01-28T19:16 full
{
let a=suncalc.getMoonIllumination(new Date('2021-01-28T19:16'));
let b=suncalc.getMoonIllumination(new Date('2021-01-28T15:25'));
return `fraction/phase at USNO time: ${a.fraction} / ${a.phase} \n fraction/phase at time I found: ${b.fraction} / ${b.phase}`;
}

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