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imlinus/index.html

Created Jan 19, 2018
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Moon Phase
<script>
Moon.phase('2018', '01', '19'); // returns `quarter-moon`
</script>
// Original Snippet: https://gist.github.com/endel/dfe6bb2fbe679781948c
// Moon.phase('2018', '01', '19');
var Moon = {
phase: function(year, month, day) {
var c = e = jd = b = 0;
if(month < 3) {
year--;
month += 12;
}
++month;
c = 365.25 * year;
e = 30.6 * month;
jd = c + e + day - 694039.09; // jd is total days elapsed
jd /= 29.5305882; // divide by the moon cycle
b = parseInt(jd); // int(jd) -> b, take integer part of jd
jd -= b; // subtract integer part to leave fractional part of original jd
b = Math.round(jd * 8); // scale fraction from 0-8 and round
if(b >= 8) b = 0; // 0 and 8 are the same so turn 8 into 0
switch(b) {
case 0: return 'new-moon'; break;
case 1: return 'waxing-crescent-moon'; break;
case 2: return 'quarter-moon'; break;
case 3: return 'waxing-gibbous-moon'; break;
case 4: return 'full-moon'; break;
case 5: return 'waning-gibbous-moon'; break;
case 6: return 'last-quarter-moon'; break;
case 7: return 'waning-crescent-moon'; break;
}
}
}
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