Wrong timezone conversion to radian

I believe you forgot to multiply the timezone by 15 before converting it to radian.

Line 164 in sky-sim.html:
`var time_zone_meridian = deg2rad(parseFloat($('#tz_sm').val()));`

There were also some unused variables in your code, like "tz_offset", which I believe was faulty because of the wrong timezone calculation.

Anyway, super kudos for your amazing project.