How to look up historical time zones by date and location

[pecore at pascolo.net]

Joel Goldstick <joel.goldstick at gmail.com> writes:

> Local Mean Time is time based on the actually astronomical position
> of the sun.  It is defined as 12 noon when the sun is at its high
> point, directly south in the sky.  This is the time you get when you
> read a sundial!

a sundial measures the Apparent Time, where the duration between two
consecutive noons is different from 24*3600 s due to the variations in
the Sun apparent angular velocity, that are originated by the Earth's
orbit eccentricity and by the inclination of the Earth's rotation
axis

these variation are small but cumulative, so the AT can be fast or
slow with respect to the LMT by as much as ±15'

don't know if the same considerations apply also in Urumqi